Improper Output Neutralization for Logs in morgan - CVE-2026-87859
Published: September 17, 2026
Vulnerability identifier: #VU150697
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-87859
CWE-ID: CWE-117
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to manipulate log fields parsed by position.
The vulnerability exists due to improper output neutralization for logs in morgan quoted log fields when logging attacker-controlled request data. A remote attacker can include an unescaped double quote in a quoted request value to manipulate log fields parsed by position.
Only log consumers that parse records by field position are affected; no newline is injected.
Affected software
morgan
How to mitigate CVE-2026-87859
Install security update from vendor's website.
morgan - update to 1.12.1