CVE-2026-84428Published

fastify vulnerable to header validation bypass via incomplete schema case normalization

Collected exploitation and prediction evidence

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

cve-program · CVE-2026-84428

Published

fastify versions before 5.12.2 implement the case-insensitive nature of HTTP header names by lowercasing names in a route's header schema before compiling it, but the transformation is incomplete: it lowercases the properties keys and the root-level required array, and does not lowercase the trigger and dependent names inside the JSON Schema Draft 7 dependencies keyword. Because Node stores request header names in lowercase, a canonical-case dependency such as requiring an authentication header whenever a privileged-mode header is present never matches, and the presence assertion is silently skipped. An unauthenticated remote client can therefore send the header that activates a privileged branch while omitting the header the dependency was meant to require, bypassing the conditional check. Users should upgrade to fastify 5.12.2 or later.

Source published: 4 Sep 2026 10:24:27 UTC
Source modified: 4 Sep 2026 16:06:04 UTC
Observed 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

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

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

euvd · EUVD-2026-70998

Published

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: Sep 4, 2026, 10:24:27 AM

dateUpdated: Sep 4, 2026, 4:06:04 PM

3 related source bulletins · separate from aliases

RHSA-2026:90321: Red Hat Security Advisory: Red Hat OpenShift Dev Spaces 3.31.0 Release.

CVE-2023-54404 · CVE-2025-62718 · CVE-2026-8643 · CVE-2026-9496 · CVE-2026-12185 · CVE-2026-13697 · CVE-2026-14682 · CVE-2026-15076 · CVE-2026-16308 · CVE-2026-17106 · CVE-2026-18427 · CVE-2026-19203 · CVE-2026-19534 · CVE-2026-39820 · CVE-2026-41178 · CVE-2026-41707 · CVE-2026-42499 · CVE-2026-42502 · CVE-2026-45416 · CVE-2026-47884 · CVE-2026-47886 · CVE-2026-47888 · CVE-2026-47890 · CVE-2026-47892 · CVE-2026-50010 · CVE-2026-55831 · CVE-2026-55833 · CVE-2026-55851 · CVE-2026-56745 · CVE-2026-56746 · CVE-2026-56819 · CVE-2026-56852 · CVE-2026-56854 · CVE-2026-58062 · CVE-2026-59280 · CVE-2026-59282 · CVE-2026-59283 · CVE-2026-59296 · CVE-2026-59313 · CVE-2026-59323 · CVE-2026-59651 · CVE-2026-59887 · CVE-2026-59899 · CVE-2026-59901 · CVE-2026-62243 · CVE-2026-64607 · CVE-2026-67213 · CVE-2026-67312 · CVE-2026-67313 · CVE-2026-67314 · CVE-2026-67320 · CVE-2026-67321 · CVE-2026-68494 · CVE-2026-68497 · CVE-2026-69152 · CVE-2026-69192 · CVE-2026-71290 · CVE-2026-71324 · CVE-2026-71325 · CVE-2026-71327 · CVE-2026-73500 · CVE-2026-73508 · CVE-2026-74835 · CVE-2026-75838 · CVE-2026-75899 · CVE-2026-75931 · CVE-2026-76169 · CVE-2026-81521 · CVE-2026-82417 · CVE-2026-82562 · CVE-2026-84292 · CVE-2026-84375 · CVE-2026-84394 · CVE-2026-84428 · CVE-2026-84445 · CVE-2026-84469 · CVE-2026-84504 · CVE-2026-84961 · CVE-2026-85062 · CVE-2026-85124 · CVE-2026-85152 · CVE-2026-85595 · CVE-2026-85597 · CVE-2026-86063 · CVE-2026-87743 · CVE-2026-88004 · CVE-2026-88007 · CVE-2026-88008 · CVE-2026-88009 · CVE-2026-88011 · CVE-2026-88012 · CVE-2026-88031 · CVE-2026-88878 · CVE-2026-88879 · CVE-2026-90711 · CVE-2026-93749 · CVE-2026-100655 · CVE-2026-100656 · CVE-2026-100666 · CVE-2026-101916 · CVE-2026-102925 · CVE-2026-102930 · CVE-2026-103435 · CVE-2026-109618 · CVE-2026-109619

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-2026:86891: 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

Source published: Sep 4, 2026, 10:24:27 AM (timezone not stated)
Source modified: Sep 4, 2026, 4:06:04 PM (timezone not stated)
Observed here: 11 Nov 2026 17:01:23 UTC
Source terms: ENISA EUVD · source terms and attribution apply

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

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

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

nvd · CVE-2026-84428

Published

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: Analyzed

Weakness classifications: CWE-178

Original publisher date fields

published: 2026-09-04T11:17:19.317

lastModified: 2026-09-15T19:54:32.420

1 source CPE criteria · context only

cpe:2.3:a:fastify:fastify:*:*:*:*:*:node.js:*:*

The original JSON retains the logical configuration operators, exclusions and version bounds.

Source published: 4 Sep 2026 11:17:19 UTC
Source modified: 15 Sep 2026 19:54:32 UTC
Observed here: 25 Oct 2026 16:19:16 UTC
Source terms: NIST NVD usage terms; underlying source attribution retained

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

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · ce714d77-add3-4f53-aff5-83d477b104bb · Secondary · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

osv · GHSA-9q9j-q6p8-xq58

Published

### Impact Fastify lowercases header-schema property names before compiling the schema, because Node.js stores request header names in lowercase. That normalization was incomplete: it lowercased only top-level `properties` keys and the root `required` array, and did not lowercase the JSON Schema Draft 7 `dependencies` keyword (its trigger keys and dependent property names) or names in nested subschemas. As a result, a header schema that uses `dependencies` to require one header when another is present (for example `X-Admin` requiring `X-Admin-Token`) never matches the lowercased request headers, so the dependency assertion is silently skipped. An unauthenticated remote client can send the header that activates a privileged path while omitting the header the dependency was meant to require, bypassing a schema-enforced security control. The header schema is idiomatic, valid JSON Schema Draft 7, and no custom validator, malformed request, or misconfiguration is required. ### Patches Header-schema names are now normalized across all schema positions (`properties`, `required`, `dependencies`, `dependentRequired`, `dependentSchemas`, and nested subschemas). Patched in fastify `5.12.2`. The fix is also included in the `6.0.0` release. Header schemas referenced through an external shared `$ref` (registered with `addSchema`) are not reached by this normalization and now emit an `FSTSEC002` startup warning; inline the header schema to keep case-insensitive assertions in effect. ### Workarounds If upgrading is not immediately possible, write header-schema names in lowercase so the `dependencies` and other case-sensitive assertions match Node's lowercased request headers, or enforce the cross-header requirement in an `onRequest` or `preValidation` hook instead of the schema.

Source published: 30 Sep 2026 23:44:27 UTC
Source modified: 1 Oct 2026 00:00:05 UTC
Observed 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

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

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

Publisher rating · HIGH