morgan vulnerable to Log Forging via unneutralized control characters in :remote-user (morgan morgan)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.33 % · percentile 26 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- openjs
- NVD status
- Analyzed
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.
Weaknesses (CWE)
- CWE-117 — Improper Output Neutralization for Logs
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | MEDIUM 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N | openjs |
| CVSS 3.1 | MEDIUM 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N | NVD · ce714d77-add3-4f53-aff5-83d477b104bb (Secondary) |
Advisories
- GHSA-4vj7-5mj6-jm8m — morgan vulnerable to Log Forging via unneutralized control characters in :remote-user
European references
- ENISA EUVD · EUVD-2026-34067
- GCVE · GCVE-0-2026-5078
CERT-FR advisories
- CERTFR-2026-AVI-1256 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1094 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:a:morgan_project:morgan:*:*:*:*:*:node.js:*:*≥ 1.2.0 < 1.11.0
Affected products
| Product | Versions |
|---|---|
| morgan · morgan | affected 1.2.0 ≤ 1.10.1 ; unaffected 1.11.0 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |