CVEvulnerability
CVE-2026-5078
5.3 MEDIUM
Official page ↗
- Status
- Analyzed
- Published
- 2026-06-03
- Last modified
- 2026-07-22
- Assigner
- ce714d77-add3-4f53-aff5-83d477b104bb
- CVSS 3.1 (ce714d77-add3-4f53-aff5-83d477b104bb)
- 5.3 MEDIUM — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- Weaknesses
- CWE-117
Description
Impact: The morgan logging middleware's :remote-user token extracts the Basic auth username from the Authorization request header and writes it to the log stream without neutralizing control characters. An unauthenticated attacker can send a crafted Authorization Basic header containing CR or LF bytes to inject forged log lines, breaking the one-request-per-line structure of access logs and enabling log forgery against downstream log consumers. The built-in combined, common, default, and short formats are affected, as well as any custom format that references :remote-user. Affected versions: morgan 1.2.0 through 1.10.1. Patches: upgrade to morgan 1.11.0, which neutralizes control characters in the :remote-user token output. Workarounds: use a custom format string that does not include :remote-user.
Affected configurations
• morgan project morgan (>= 1.2.0 < 1.11.0)
Related
Weakness · CWE (1)
- CWE-117 Improper Output Neutralization for Logs weakness
References
- https://cna.openjsf.org/security-advisories.html Third Party Advisory
- https://github.com/expressjs/morgan/security/advisories/GHSA-4vj7-5mj6-jm8m Mitigation, Vendor Advisory