GHSA-4vj7-5mj6-jm8m: morgan vulnerable to Log Forging via unneutralized control characters in :remote-user
Impact
Morgan's :remote-user token extracts the Basic auth username from the Authorization header and writes it to the log stream without neutralizing control characters. An attacker can send a crafted Authorization: Basic header containing CR/LF characters to inject forged log lines, corrupting the one-request-per-line structure of access logs.
The built-in combined, common, default, and short formats are affected, as well as any custom format that includes :remote-user.
Patches
Users should upgrade to version 1.11.0.
Workarounds
Use a custom format string that does not include :remote-user.
Details
Original advisory: https://github.com/advisories/GHSA-4vj7-5mj6-jm8m
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Low exploitation riskCVE-2026-50780.25% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 16% of all scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-5078 | coverage & exploitation status | NVD · CVE.org |
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