morgan vulnerable to Log Forging via unescaped Unicode line separators

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-15603
StatePUBLISHED
Assigneropenjs
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-28 16:17:07 UTC
Updated2026-08-31 17:11:12 UTC
Descriptionmorgan is an HTTP request logger middleware for Node.js. In versions prior to 1.12.0, the internal helper that escapes log token values did not neutralize the Unicode line separator characters U+0085 (Next Line), U+2028 (Line Separator), and U+2029 (Paragraph Separator). An unauthenticated remote client can place these characters in an attacker-controlled log token, for example a Basic auth username surfaced through the remote-user token, so that Unicode-aware downstream log processing splits a single request log into multiple logical records. This is a log forging issue (CWE-117) and an incomplete-fix follow-up to CVE-2026-5078, which only addressed ASCII control characters. The issue is fixed in morgan 1.12.0, which extends the escaping set to cover these Unicode line separators. Upgrade to morgan 1.12.0 to remediate.

Risk And Classification

Primary CVSS: v3.1 5.3 MEDIUM from ce714d77-add3-4f53-aff5-83d477b104bb

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

EPSS: 0.002350000 probability, percentile 0.142880000 (date 2026-09-01)

Problem Types: CWE-117 | CWE-117 CWE-117: Improper Output Neutralization for Logs

VersionSourceTypeScoreSeverityVector
3.1ce714d77-add3-4f53-aff5-83d477b104bbSecondary5.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
3.1CNACVSS5.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

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

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Morgan Project Morgan All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Morgan Morgan affected 1.12.0 semver Not specified

References

ReferenceSourceLinkTags
cna.openjsf.org/security-advisories.html ce714d77-add3-4f53-aff5-83d477b104bb cna.openjsf.org Third Party Advisory
github.com/expressjs/morgan/security/advisories/GHSA-jxfw-x594-9x9m ce714d77-add3-4f53-aff5-83d477b104bb github.com Vendor Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: mfazrinizar (en)

CNA: UlisesGascon (en)

CNA: jonchurch (en)

CNA: bjohansebas (en)

CNA: iaohkut-from-NightWolf-Team (en)

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