# CVE-2026-5078

## Summary

- **CVE ID:** CVE-2026-5078
- **Severity:** MEDIUM
- **CVSS Score:** 5.3 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N)
- **CWE:** CWE-117
- **Published:** Jun 3, 2026
- **Last Modified:** Jun 3, 2026

## 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

- morgan — morgan (1.2.0)
- morgan — morgan (1.11.0)

## References

- [CNA](https://github.com/expressjs/morgan/security/advisories/GHSA-4vj7-5mj6-jm8m)
- [CNA](https://cna.openjsf.org/security-advisories.html)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.33%
- **EPSS Percentile:** 26.1

---
_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._