---
cve: "CVE-2026-5078"
severity: "MEDIUM"
cvss: 5.3
epss: "33%"
vendor: "morgan"
kev: false
exploited: false
published: "2026-06-03 05:56:49"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-03T07:51:17+02:00"
---

# CVE-2026-5078

> 5.3 MEDIUM · 🧪 PoC

## Beschreibung

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.

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Keine | good |
| I Integrität | Gering | warn |
| A Verfügbarkeit | Keine | good |

## Patch verfügbar (OSV)

- e0e6f17574db56396f8e60ebb03bb7aaaeb9cc6f (Commit)

## Referenzen

- <https://github.com/expressjs/morgan/security/advisories/GHSA-4vj7-5mj6-jm8m>
- <https://cna.openjsf.org/security-advisories.html>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-5078) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_