GHSA-9f6g-j8ch-79g4Published

morgan vulnerable to Log Injection via unescaped double quote in quoted log fields

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-2026-87859

Published

morgan is an HTTP request logger middleware for Node.js. In versions before 1.12.1, its escapeLogField() function does not escape the double quote character, which delimits the quoted fields of the Apache combined log format that morgan emits. An unauthenticated remote attacker who controls a value written to a quoted field, such as the User-Agent or Referer header, can include a double quote to close that field early, so a log consumer that parses the log by field position reads attacker-supplied text as the following field. In the built-in formats this makes the recorded value differ from the value that was sent, and in custom formats that quote an attacker-controlled token before a server-controlled one it can forge values such as the response status. No newline is injected, so record separation stays intact. The issue is fixed in morgan 1.12.1, which escapes the double quote. Users should upgrade to morgan 1.12.1 or later.

Source published: 11 Sep 2026 09:15:19 UTC
Source modified: 11 Sep 2026 11:32:10 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 · 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

euvd · EUVD-2026-76027

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 11, 2026, 9:15:19 AM

dateUpdated: Sep 11, 2026, 11:32:10 AM

Source published: Sep 11, 2026, 9:15:19 AM (timezone not stated)
Source modified: Sep 11, 2026, 11:32:10 AM (timezone not stated)
Observed here: 11 Nov 2026 17:03:05 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 · 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

nvd · CVE-2026-87859

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: Awaiting Analysis

Weakness classifications: CWE-117

Original publisher date fields

published: 2026-09-11T10:16:53.253

lastModified: 2026-09-16T19:40:00.317

Source published: 11 Sep 2026 10:16:53 UTC
Source modified: 16 Sep 2026 19:40:00 UTC
Observed here: 25 Oct 2026 16:19:22 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 · 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

osv · GHSA-9f6g-j8ch-79g4

Published

### Impact Morgan writes attacker-controlled request data to the access log. Its escaping (added in 1.11.0 and 1.12.0) neutralizes control characters, the Unicode line separators, and backslash, but not the double quote (`0x22`), which is the field delimiter of the Apache combined log format morgan emits. An attacker who controls a quoted field (`:user-agent`, `:referrer`, the request URL, or the Basic auth `:remote-user`) can inject a double quote to close the field early and forge additional fields in the log record. The `combined`, `common`, and `default` formats, and any custom format that quotes a token, are affected. This is an incomplete fix of CVE-2026-5078 and CVE-2026-15603. ### Patches Users should upgrade to version 1.12.1. ### Workarounds Update to version 1.12.1.

Source published: 28 Sep 2026 21:33:08 UTC
Source modified: 28 Sep 2026 21:45:03 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:L/A:N

Publisher rating · MODERATE