CVE-2026-5078

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.
Configurations

No configuration.

History

03 Jun 2026, 08:16

Type Values Removed Values Added
New CVE

Information

Published : 2026-06-03 08:16

Updated : 2026-06-04 16:40


NVD link : CVE-2026-5078

Mitre link : CVE-2026-5078

CVE.ORG link : CVE-2026-5078


JSON object : View

Products Affected

No product.

CWE
CWE-117

Improper Output Neutralization for Logs