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 products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| morgan | morgan | 1.2.0 – ≤ 1.10.1 | 1.11.0 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | node-morgan | 1.12.0+~1.9.10-1 | — |
| Debian 13 | node-morgan | No fix yet | — |
| Debian 12 | node-morgan | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | node-morgan | No fix yet | — |
| Ubuntu 26.04 LTS | node-morgan | No fix yet | — |
| Ubuntu 25.10 | node-morgan | No fix yet | — |
| Ubuntu 24.04 LTS | node-morgan | No fix yet | — |
| Ubuntu 22.04 LTS | node-morgan | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Hardened Images 1 | nodejs24 +6 | 24.18.0-0.3.hum1 | RHSA-2026:38236 |
| Red Hat Hardened Images 1 | nodejs24-npm | 11.16.0-1.24.18.0.0.3.hum1 | RHSA-2026:38236 |
| Red Hat Hardened Images 1 | v8-13.6-devel | 13.6.233.17-1.24.18.0.0.3.hum1 | RHSA-2026:38236 |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | tileserver-gl | 5.6.0-r10 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| npm | morgan | >= 1.2.0, < 1.11.0 | 1.11.0 | GHSA-4vj7-5mj6-jm8m |
Advisories 1
- RHSA-2026:38236 Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update Red Hat Security Advisories (RHSA) · Oct 20, 2026