GHSA-r28c-9q8g-f849Published

PostCSS: Path Traversal in Previous Source Map Auto-Loading (sourceMappingURL) leads to Arbitrary .map File Disclosure

Exploitation and risk

CISA KEV lists vulnerabilities known to be exploited. FIRST EPSS estimates the likelihood of exploitation in the next 30 days. An unavailable score does not mean zero risk.

Which CVEs have scores here?

This view includes predictions for CVE identifiers explicitly listed in public NuGet advisories. Microsoft release pages have their own prediction coverage. Check source status for the scope and latest checks.

No exploitation or prediction data is available here for these CVEs. This does not mean they are safe or unlikely to be exploited.

cve-program · CVE-2026-73646

Published

PostCSS takes a CSS file and provides an API to analyze and modify its rules by transforming the rules into an Abstract Syntax Tree. Prior to 8.5.18, lib/previous-map.js loadMap() passes attacker-controlled sourceMappingURL values to join(dirname(opts.from), annotation), and loadFile() permits traversed or absolute .map paths, allowing untrusted CSS processed without map: false to disclose sourcesContent from arbitrary reachable .map files through result.map. This issue is fixed in version 8.5.18.

Source published: 17 Aug 2026 15:35:13 UTC
Source modified: 17 Aug 2026 16:36:37 UTC
Saved here: 23 Oct 2026 15:48:27 UTC
Source terms: CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

Source: cve-program · CVE Program Terms of Use. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS 3.1 · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

euvd · EUVD-2026-60239

Published

Additional publisher context

EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.

Original publisher date fields

datePublished: Aug 17, 2026, 3:35:13 PM

dateUpdated: Aug 17, 2026, 4:36:37 PM

19 related source bulletins · separate from aliases

RHSA-2026:67540: Red Hat Security Advisory: Red Hat Advanced Cluster Management for Kubernetes v2.13.12 security update

CVE-2025-53547 · CVE-2026-41178 · CVE-2026-42151 · CVE-2026-48586 · CVE-2026-55969 · CVE-2026-56852 · CVE-2026-66780 · CVE-2026-71556 · CVE-2026-73646 · CVE-2026-89060

RHSA-2026:83598: Red Hat Security Advisory: RHTAS 1.4.4 - Red Hat Trusted Artifact Signer Release

CVE-2026-4800 · CVE-2026-41178 · CVE-2026-45623 · CVE-2026-56854 · CVE-2026-59873 · CVE-2026-59874 · CVE-2026-67213 · CVE-2026-67214 · CVE-2026-69153 · CVE-2026-73086 · CVE-2026-73088 · CVE-2026-73089 · CVE-2026-73500 · CVE-2026-73643 · CVE-2026-73646 · CVE-2026-84375 · CVE-2026-84445 · CVE-2026-93749

RHSA-2026:87410: Red Hat Security Advisory: RHOAI 2.25.12 - Red Hat OpenShift AI

CVE-2024-12224 · CVE-2025-14920 · CVE-2025-14921 · CVE-2025-14924 · CVE-2025-14925 · CVE-2025-14926 · CVE-2025-14927 · CVE-2025-14928 · CVE-2025-14929 · CVE-2025-14930 · CVE-2025-61726 · CVE-2025-61729 · CVE-2026-5241 · CVE-2026-5497 · CVE-2026-6734 · CVE-2026-8643 · CVE-2026-9697 · CVE-2026-11822 · CVE-2026-11824 · CVE-2026-12151 · CVE-2026-12860 · CVE-2026-15143 · CVE-2026-15574 · CVE-2026-15679 · CVE-2026-15925 · CVE-2026-16221 · CVE-2026-18427 · CVE-2026-18446 · CVE-2026-18949 · CVE-2026-19481 · CVE-2026-19484 · CVE-2026-19534 · CVE-2026-25681 · CVE-2026-25960 · CVE-2026-27136 · CVE-2026-28390 · CVE-2026-28684 · CVE-2026-31812 · CVE-2026-32283 · CVE-2026-33186 · CVE-2026-33805 · CVE-2026-33811 · CVE-2026-33814 · CVE-2026-34993 · CVE-2026-39821 · CVE-2026-39852 · CVE-2026-39892 · CVE-2026-40682 · CVE-2026-41178 · CVE-2026-42502 · CVE-2026-42561 · CVE-2026-44431 · CVE-2026-44432 · CVE-2026-44660 · CVE-2026-44705 · CVE-2026-45820 · CVE-2026-47219 · CVE-2026-48526 · CVE-2026-48710 · CVE-2026-48746 · CVE-2026-49114 · CVE-2026-49825 · CVE-2026-49855 · CVE-2026-50559 · CVE-2026-54283 · CVE-2026-54399 · CVE-2026-54428 · CVE-2026-55831 · CVE-2026-55833 · CVE-2026-56121 · CVE-2026-56746 · CVE-2026-56819 · CVE-2026-56853 · CVE-2026-56858 · CVE-2026-56859 · CVE-2026-56860 · CVE-2026-56862 · CVE-2026-58059 · CVE-2026-59296 · CVE-2026-59879 · CVE-2026-59884 · CVE-2026-59885 · CVE-2026-59886 · CVE-2026-59899 · CVE-2026-62243 · CVE-2026-62384 · CVE-2026-63209 · CVE-2026-63374 · CVE-2026-65898 · CVE-2026-65918 · CVE-2026-66007 · CVE-2026-67213 · CVE-2026-67214 · CVE-2026-67312 · CVE-2026-68494 · CVE-2026-68497 · CVE-2026-68770 · CVE-2026-69097 · CVE-2026-69112 · CVE-2026-69152 · CVE-2026-69153 · CVE-2026-69243 · CVE-2026-69244 · CVE-2026-71281 · CVE-2026-73086 · CVE-2026-73088 · CVE-2026-73089 · CVE-2026-73415 · CVE-2026-73417 · CVE-2026-73502 · CVE-2026-73508 · CVE-2026-73620 · CVE-2026-73622 · CVE-2026-73623 · CVE-2026-73624 · CVE-2026-73625 · CVE-2026-73627 · CVE-2026-73646 · CVE-2026-75838 · CVE-2026-75899 · CVE-2026-75931 · CVE-2026-75975 · CVE-2026-76098 · CVE-2026-76169 · CVE-2026-76172 · CVE-2026-76222 · CVE-2026-76905 · CVE-2026-77354 · CVE-2026-77874 · CVE-2026-78676 · CVE-2026-78677 · CVE-2026-78679 · CVE-2026-78682 · CVE-2026-79674 · CVE-2026-79675 · CVE-2026-80205 · CVE-2026-81722 · CVE-2026-81724 · CVE-2026-81727 · CVE-2026-82397 · CVE-2026-82417 · CVE-2026-84292 · CVE-2026-84375 · CVE-2026-84394 · CVE-2026-84428 · CVE-2026-84445 · CVE-2026-84469 · CVE-2026-84504 · CVE-2026-84782 · CVE-2026-84961 · CVE-2026-85124 · CVE-2026-85152 · CVE-2026-85525 · CVE-2026-86049 · CVE-2026-86332 · CVE-2026-87776 · CVE-2026-87817 · CVE-2026-87819 · CVE-2026-88029 · CVE-2026-88031 · CVE-2026-89418 · CVE-2026-89425 · CVE-2026-91777 · CVE-2026-91990 · CVE-2026-92599 · CVE-2026-93599 · CVE-2026-93657 · CVE-2026-93749 · CVE-2026-96749 · CVE-2026-102831 · CVE-2026-102925 · CVE-2026-102930 · CVE-2026-102937 · CVE-2026-102938 · CVE-2026-103262 · CVE-2026-104851 · CVE-2026-105744

RHSA-2026:70829: Red Hat Security Advisory: RHTAS 1.3.8 - Red Hat Trusted Artifact Signer Release

CVE-2026-41178 · CVE-2026-45736 · CVE-2026-48779 · CVE-2026-56854 · CVE-2026-59869 · CVE-2026-73086 · CVE-2026-73088 · CVE-2026-73089 · CVE-2026-73500 · CVE-2026-73646

RHSA-2026:68765: Red Hat Security Advisory: Technical preview of the satellite/iop-vulnerability-frontend-rhel9 container image

CVE-2026-12143 · CVE-2026-45819 · CVE-2026-59879 · CVE-2026-67313 · CVE-2026-67314 · CVE-2026-67320 · CVE-2026-67321 · CVE-2026-73088 · CVE-2026-73089 · CVE-2026-73646 · CVE-2026-75931 · CVE-2026-75975 · CVE-2026-76172

WID-SEC-W-2026-3596: IBM App Connect Enterprise: Mehrere Schwachstellen

CVE-2022-35948 · CVE-2026-13149 · CVE-2026-14257 · CVE-2026-15157 · CVE-2026-1527 · CVE-2026-16728 · CVE-2026-16729 · CVE-2026-18149 · CVE-2026-18540 · CVE-2026-19534 · CVE-2026-2391 · CVE-2026-45820 · CVE-2026-54272 · CVE-2026-63670 · CVE-2026-67213 · CVE-2026-67214 · CVE-2026-69152 · CVE-2026-69192 · CVE-2026-69198 · CVE-2026-73566 · CVE-2026-73646 · CVE-2026-77037 · CVE-2026-77063 · CVE-2026-77078 · CVE-2026-82333 · CVE-2026-82417 · CVE-2026-82562 · CVE-2026-83605 · CVE-2026-83606 · CVE-2026-83607 · CVE-2026-83608 · CVE-2026-83609 · CVE-2026-83610 · CVE-2026-83611 · CVE-2026-83612 · CVE-2026-83613 · CVE-2026-83614 · CVE-2026-83615 · CVE-2026-83616 · CVE-2026-83618 · CVE-2026-83619 · CVE-2026-84292 · CVE-2026-84371 · CVE-2026-84375 · CVE-2026-84890 · CVE-2026-84933 · CVE-2026-84947 · CVE-2026-84961 · CVE-2026-85008 · CVE-2026-85014 · CVE-2026-85024 · CVE-2026-85152

RHSA-2026:62260: Red Hat Security Advisory: Red Hat OpenShift Dev Spaces 3.30.0 Release.

CVE-2025-55163 · CVE-2026-8286 · CVE-2026-9277 · CVE-2026-9547 · CVE-2026-9563 · CVE-2026-10050 · CVE-2026-10051 · CVE-2026-12143 · CVE-2026-12151 · CVE-2026-13149 · CVE-2026-15075 · CVE-2026-15076 · CVE-2026-27136 · CVE-2026-34986 · CVE-2026-39820 · CVE-2026-39831 · CVE-2026-39835 · CVE-2026-40898 · CVE-2026-40983 · CVE-2026-40984 · CVE-2026-41242 · CVE-2026-41695 · CVE-2026-41716 · CVE-2026-42264 · CVE-2026-42499 · CVE-2026-44705 · CVE-2026-45149 · CVE-2026-45416 · CVE-2026-45623 · CVE-2026-45674 · CVE-2026-46597 · CVE-2026-46681 · CVE-2026-47691 · CVE-2026-48020 · CVE-2026-48068 · CVE-2026-48491 · CVE-2026-49978 · CVE-2026-50010 · CVE-2026-50193 · CVE-2026-53488 · CVE-2026-53492 · CVE-2026-53622 · CVE-2026-54399 · CVE-2026-54428 · CVE-2026-54512 · CVE-2026-54513 · CVE-2026-54763 · CVE-2026-55831 · CVE-2026-55833 · CVE-2026-56745 · CVE-2026-56746 · CVE-2026-56819 · CVE-2026-59296 · CVE-2026-59869 · CVE-2026-59873 · CVE-2026-59874 · CVE-2026-59877 · CVE-2026-59888 · CVE-2026-59899 · CVE-2026-65600 · CVE-2026-65601 · CVE-2026-67213 · CVE-2026-67214 · CVE-2026-68494 · CVE-2026-69152 · CVE-2026-69153 · CVE-2026-73086 · CVE-2026-73566 · CVE-2026-73646 · CVE-2026-75838

RHSA-2026:68748: Red Hat Security Advisory: General availability of the satellite/iop-advisor-frontend-rhel9 container image

CVE-2026-12143 · CVE-2026-59869 · CVE-2026-67313 · CVE-2026-67314 · CVE-2026-67320 · CVE-2026-67321 · CVE-2026-73086 · CVE-2026-73088 · CVE-2026-73089 · CVE-2026-73646 · CVE-2026-75899 · CVE-2026-75931 · CVE-2026-75975 · CVE-2026-76172 · CVE-2026-84292 · CVE-2026-84375 · CVE-2026-84394

RHSA-2026:68750: Red Hat Security Advisory: General availability of the satellite/iop-host-inventory-frontend-rhel9 container image

CVE-2026-73646 · CVE-2026-75899 · CVE-2026-75931 · CVE-2026-75975 · CVE-2026-76172 · CVE-2026-84292 · CVE-2026-84394

RHSA-2026:68754: Red Hat Security Advisory: Red Hat OpenShift Dev Spaces 3.30.1 Release.

CVE-2026-4800 · CVE-2026-45623 · CVE-2026-45819 · CVE-2026-47219 · CVE-2026-48801 · CVE-2026-54272 · CVE-2026-55831 · CVE-2026-55833 · CVE-2026-56745 · CVE-2026-56746 · CVE-2026-56819 · CVE-2026-59887 · CVE-2026-59899 · CVE-2026-67213 · CVE-2026-67312 · CVE-2026-67313 · CVE-2026-67314 · CVE-2026-67320 · CVE-2026-67321 · CVE-2026-69152 · CVE-2026-69153 · CVE-2026-69192 · CVE-2026-71436 · CVE-2026-73086 · CVE-2026-73088 · CVE-2026-73089 · CVE-2026-73508 · CVE-2026-73566 · CVE-2026-73646 · CVE-2026-75899 · CVE-2026-75931 · CVE-2026-75975 · CVE-2026-76172 · CVE-2026-82562 · CVE-2026-84292 · CVE-2026-84375 · CVE-2026-84394

RHSA-2026:67538: Red Hat Security Advisory: Red Hat Advanced Cluster Management for Kubernetes v2.11.12 security update

CVE-2026-27136 · CVE-2026-41178 · CVE-2026-42151 · CVE-2026-42154 · CVE-2026-42502 · CVE-2026-48586 · CVE-2026-55969 · CVE-2026-56852 · CVE-2026-66780 · CVE-2026-71556 · CVE-2026-73646

RHSA-2026:86891: Red Hat Security Advisory: RHOAI 3.5.2 - Red Hat OpenShift AI

CVE-2024-14029 · CVE-2026-13697 · CVE-2026-15679 · CVE-2026-15789 · CVE-2026-18427 · CVE-2026-19534 · CVE-2026-37237 · CVE-2026-49825 · CVE-2026-49855 · CVE-2026-54284 · CVE-2026-56859 · CVE-2026-59296 · CVE-2026-59893 · CVE-2026-62243 · CVE-2026-62384 · CVE-2026-63209 · CVE-2026-63374 · CVE-2026-66007 · CVE-2026-68494 · CVE-2026-68497 · CVE-2026-69097 · CVE-2026-69112 · CVE-2026-69152 · CVE-2026-69243 · CVE-2026-69244 · CVE-2026-71281 · CVE-2026-71491 · CVE-2026-73417 · CVE-2026-73502 · CVE-2026-73508 · CVE-2026-73646 · CVE-2026-75838 · CVE-2026-75899 · CVE-2026-75931 · CVE-2026-75975 · CVE-2026-76098 · CVE-2026-76169 · CVE-2026-76172 · CVE-2026-76222 · CVE-2026-76905 · CVE-2026-77354 · CVE-2026-77874 · CVE-2026-78676 · CVE-2026-78677 · CVE-2026-78679 · CVE-2026-78682 · CVE-2026-79674 · CVE-2026-79675 · CVE-2026-80205 · CVE-2026-81722 · CVE-2026-81724 · CVE-2026-81725 · CVE-2026-81726 · CVE-2026-81727 · CVE-2026-82397 · CVE-2026-82417 · CVE-2026-84292 · CVE-2026-84375 · CVE-2026-84381 · CVE-2026-84382 · CVE-2026-84394 · CVE-2026-84428 · CVE-2026-84445 · CVE-2026-84469 · CVE-2026-84504 · CVE-2026-84782 · CVE-2026-84961 · CVE-2026-85124 · CVE-2026-85152 · CVE-2026-85525 · CVE-2026-86332 · CVE-2026-87776 · CVE-2026-87817 · CVE-2026-87819 · CVE-2026-88029 · CVE-2026-88031 · CVE-2026-89425 · CVE-2026-91990 · CVE-2026-93348 · CVE-2026-93599 · CVE-2026-93657 · CVE-2026-93749 · CVE-2026-96749 · CVE-2026-96775 · CVE-2026-102925 · CVE-2026-102930 · CVE-2026-102937 · CVE-2026-102938 · CVE-2026-102990 · CVE-2026-104851 · CVE-2026-104852 · CVE-2026-104861 · CVE-2026-104873

RHSA-2026:54520: Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update

CVE-2026-73086 · CVE-2026-73646

RHSA-2026:50287: Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update

CVE-2026-69153 · CVE-2026-72815 · CVE-2026-73086 · CVE-2026-73646

RHSA-2026:68755: Red Hat Security Advisory: Technical preview of the satellite/iop-vulnerability-frontend-rhel9 container image

CVE-2026-12143 · CVE-2026-45623 · CVE-2026-45819 · CVE-2026-67313 · CVE-2026-67314 · CVE-2026-67320 · CVE-2026-67321 · CVE-2026-73086 · CVE-2026-73088 · CVE-2026-73089 · CVE-2026-73646 · CVE-2026-75899 · CVE-2026-75931 · CVE-2026-75975 · CVE-2026-76172

RHSA-2026:68756: Red Hat Security Advisory: General availability of the satellite/iop-host-inventory-frontend-rhel9 container image

CVE-2026-59879 · CVE-2026-73646 · CVE-2026-75899 · CVE-2026-75931 · CVE-2026-75975 · CVE-2026-76172 · CVE-2026-84292 · CVE-2026-84394

WID-SEC-W-2026-4056: Atlassian Produkte (Bamboo, Bitbucket, Confluence, Crucible, Fisheye und Jira): Mehrere Schwachstellen

CVE-2026-101898 · CVE-2026-101901 · CVE-2026-101903 · CVE-2026-101905 · CVE-2026-101906 · CVE-2026-101907 · CVE-2026-101909 · CVE-2026-12185 · CVE-2026-12802 · CVE-2026-12860 · CVE-2026-13006 · CVE-2026-13676 · CVE-2026-14682 · CVE-2026-18036 · CVE-2026-19534 · CVE-2026-19693 · CVE-2026-41842 · CVE-2026-41845 · CVE-2026-41850 · CVE-2026-49434 · CVE-2026-50750 · CVE-2026-53404 · CVE-2026-54399 · CVE-2026-54428 · CVE-2026-54512 · CVE-2026-54513 · CVE-2026-55153 · CVE-2026-55831 · CVE-2026-55833 · CVE-2026-56624 · CVE-2026-56745 · CVE-2026-58061 · CVE-2026-58062 · CVE-2026-59641 · CVE-2026-59645 · CVE-2026-59651 · CVE-2026-59903 · CVE-2026-62243 · CVE-2026-65182 · CVE-2026-65183 · CVE-2026-65637 · CVE-2026-65927 · CVE-2026-66422 · CVE-2026-67213 · CVE-2026-67214 · CVE-2026-68494 · CVE-2026-68495 · CVE-2026-68497 · CVE-2026-68498 · CVE-2026-68525 · CVE-2026-68569 · CVE-2026-68763 · CVE-2026-71888 · CVE-2026-71889 · CVE-2026-71891 · CVE-2026-73086 · CVE-2026-73507 · CVE-2026-73508 · CVE-2026-73634 · CVE-2026-73635 · CVE-2026-73646 · CVE-2026-75140 · CVE-2026-75595 · CVE-2026-75596 · CVE-2026-75975 · CVE-2026-76172 · CVE-2026-77185 · CVE-2026-84292 · CVE-2026-84375 · CVE-2026-93488 · CVE-2026-93491 · CVE-2026-93558 · CVE-2026-93690 · CVE-2026-93748 · CVE-2026-93994

openSUSE-SU-2026:12070-1: velociraptor-0.76.7.0.git145.b60ef1146-1.1 on GA media

CVE-2025-0914 · CVE-2026-12143 · CVE-2026-14257 · CVE-2026-17535 · CVE-2026-18348 · CVE-2026-18636 · CVE-2026-18638 · CVE-2026-18639 · CVE-2026-18860 · CVE-2026-27601 · CVE-2026-29074 · CVE-2026-41650 · CVE-2026-45623 · CVE-2026-49356 · CVE-2026-5329 · CVE-2026-53550 · CVE-2026-55602 · CVE-2026-56852 · CVE-2026-59869 · CVE-2026-6290 · CVE-2026-64951 · CVE-2026-64952 · CVE-2026-64954 · CVE-2026-65903 · CVE-2026-65912 · CVE-2026-65913 · CVE-2026-65914 · CVE-2026-67314 · CVE-2026-67320 · CVE-2026-6863 · CVE-2026-69152 · CVE-2026-69153 · CVE-2026-6948 · CVE-2026-73086 · CVE-2026-73646 · CVE-2026-73650 · CVE-2026-7572 · CVE-2026-7573 · CVE-2026-84369 · CVE-2026-84370

RHSA-2026:68681: Red Hat Security Advisory: Migration Toolkit for Containers (MTC) 1.8.17 update

CVE-2026-14257 · CVE-2026-16221 · CVE-2026-27145 · CVE-2026-33186 · CVE-2026-33818 · CVE-2026-42504 · CVE-2026-56852 · CVE-2026-56853 · CVE-2026-56859 · CVE-2026-56860 · CVE-2026-56862 · CVE-2026-59869 · CVE-2026-59873 · CVE-2026-59874 · CVE-2026-67313 · CVE-2026-67314 · CVE-2026-67320 · CVE-2026-67321 · CVE-2026-69152 · CVE-2026-69192 · CVE-2026-73088 · CVE-2026-73089 · CVE-2026-73566 · CVE-2026-73643 · CVE-2026-73646 · CVE-2026-75899 · CVE-2026-75931 · CVE-2026-75975 · CVE-2026-76172 · CVE-2026-76844 · CVE-2026-82417 · CVE-2026-84292 · CVE-2026-84375 · CVE-2026-84394

Source published: Aug 17, 2026, 3:35:13 PM (timezone not stated)
Source modified: Aug 17, 2026, 4:36:37 PM (timezone not stated)
Saved here: 14 Nov 2026 06:05:34 UTC
Source terms: ENISA EUVD · source terms and attribution apply

Original source record · Cite this exact observation · Complete original publisher JSON

Source: euvd · ENISA EUVD · source terms and attribution apply. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

EUVD CVSS 3.1 · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

nvd · CVE-2026-73646

Published

Additional publisher context

NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.

Source analysis status: Awaiting Analysis

Weakness classifications: CWE-22

Original publisher date fields

published: 2026-08-17T16:17:47.257

lastModified: 2026-09-18T20:05:53.723

Source published: 17 Aug 2026 16:17:47 UTC
Source modified: 18 Sep 2026 20:05:53 UTC
Saved here: 25 Oct 2026 15:19:09 UTC
Source terms: NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

Source: nvd · NIST NVD usage terms; underlying source attribution retained. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS 3.1 · [email protected] · Secondary · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

osv · GHSA-r28c-9q8g-f849

Published

## Vulnerability Details **File**: `lib/previous-map.js` **Line**: 87-98 (`loadFile`), 129-144 (`loadMap`) ### Root Cause PostCSS auto-detects a `/*# sourceMappingURL=... */` comment inside the CSS text it is asked to parse and, unless the caller explicitly passes `map: false`, attempts to load that path from disk as a "previous source map." This happens on every `postcss.parse()` / `postcss().process()` call by default (opt-out, not opt-in). `loadMap()` builds the candidate path via `join(dirname(opts.from), annotation)`, where `annotation` is the raw, attacker-controlled string from the CSS comment. `path.join()` normalizes but does not sandbox `..` segments, so a `../../../` prefix walks the resolved path outside the intended directory. If `opts.from` is not set at all, the annotation is used completely unmodified — an absolute path in the CSS comment is read verbatim. 8.5.12 already fixed a strictly worse variant of this (any file, any extension, could be read) by requiring the resolved path to end in `.map` (`loadFile()`). That fix did not address the traversal itself, only the target extension. Since the `join(dirname(file), map)` logic has existed unchanged since PostCSS 8.0.0 (Feb 2020), any file ending in `.map` remains readable through this path in the current release (8.5.16). Once loaded, `MapGenerator.isMap()` treats the mere presence of a loaded "previous map" as an implicit request to generate `result.map`, even when the caller never set the `map` option. If the loaded map has a `sourcesContent` field (common for maps emitted by bundlers/transpilers), that content is merged into `result.map` and returned to the caller — disclosing the traversed-to file's content to whoever supplied the CSS. ### Attack Scenario 1. A service accepts user-submitted CSS and runs it through PostCSS to lint/format/transform it, e.g. `postcss().process(userCss, { from: '/app/uploads/user123/input.css', to: '/app/uploads/user123/output.css' })` — idiomatic usage; `map` option untouched. 2. Attacker submits CSS containing `/*# sourceMappingURL=../../../../some/other/app/dist/bundle.js.map */` (or an absolute path if `from` is unset). 3. PostCSS reads that `.map` file and folds its `sourcesContent` into `result.map`. 4. The service does what most build pipelines do with a truthy `result.map` — writes it next to the CSS output or returns it via API (source maps are meant to be consumed by browser devtools, so this is commonly public/served). 5. Attacker retrieves the emitted map and reads out the traversed file's content. ### Impact Disclosure of the contents of arbitrary `.map` files reachable via path traversal (or absolute path when `from` is unset) from the process's filesystem. Affects any application processing CSS it does not fully trust without explicitly passing `map: false`. No authentication or user interaction beyond submitting CSS text is required. ### Vulnerable Code ```js loadFile(path, cssFile, trusted) { if (!trusted && !this.unsafeMap) { if (!/\.map$/i.test(path)) { return undefined } } this.root = dirname(path) if (existsSync(path)) { this.mapFile = path return readFileSync(path, 'utf-8').toString().trim() } } loadMap(file, prev) { ... } else if (this.annotation) { let map = this.annotation if (file) map = join(dirname(file), map) let unknown = this.loadFile(map, file, false) ... } } ``` ### Recommended Fix Constrain the resolved path to remain inside the CSS file's own directory instead of relying solely on a filename-extension check: ```js loadFile(path, cssFile, trusted) { if (!trusted && !this.unsafeMap) { if (!/\.map$/i.test(path)) { return undefined } if (!cssFile) return undefined let root = resolve(dirname(cssFile)) let resolvedPath = resolve(root, path) if (resolvedPath !== root && !resolvedPath.startsWith(root + sep)) { return undefined } } this.root = dirname(path) if (existsSync(path)) { this.mapFile = path return readFileSync(path, 'utf-8').toString().trim() } } ``` I've implemented, tested (full existing test suite — 660/660 passing, plus new PoC-based regression checks for both the traversal and legitimate same-directory cases), and can share this fix on request or via a private fork if invited. ### Verification Dynamically confirmed on v8.5.16 (current npm release / repo HEAD) via a standalone Node.js harness against `lib/postcss.js`: a "secret" `.map` file placed two directories outside a simulated project directory was read via a crafted `sourceMappingURL` comment in otherwise-innocuous CSS, with its `sourcesContent` appearing verbatim in `result.map.toString()` — with no `map` option set by the caller. A second harness confirmed the simpler no-`from` case reads an absolute path directly. A third harness confirmed `map: false` is the only current workaround. The attached fix branch closes both vectors while keeping all 660 existing unit tests green.

Source published: 24 Jul 2026 16:24:55 UTC
Source modified: 10 Sep 2026 03:50:52 UTC
Saved here: 24 Oct 2026 13:17:17 UTC
Source terms: GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

Source: osv · GitHub Advisory Database · CC-BY-4.0. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Publisher rating · HIGH