CVE-2026-15603

morgan 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.

CVSS v3 5.3 MEDIUM

5.3^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 3.9 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact LOW

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://cna.openjsf.org/security-advisories.html	Third Party Advisory
https://github.com/expressjs/morgan/security/advisories/GHSA-jxfw-x594-9x9m	Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:morgan_project:morgan:*:*:*:*:*:node.js:*:*

History

No history.

Information

Published : 2026-08-28 16:17

Updated : 2026-08-31 17:11

NVD link : CVE-2026-15603

Mitre link : CVE-2026-15603

CVE.ORG link : CVE-2026-15603

JSON object : View

Products Affected

morgan_project

morgan

CWE

CWE-117

Improper Output Neutralization for Logs

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