CVE-2026-87859

A flaw was found in morgan, an HTTP request logger middleware for Node.js. An unauthenticated remote attacker can exploit this vulnerability by injecting an unescaped double quote into a log field they control, such as the User-Agent or Referer header. This causes the log field to close prematurely, leading a log parsing system to misinterpret subsequent attacker-controlled text as a different log field. This could result in the forging of log entries, potentially impacting the integrity of log data.

A log injection flaw in the morgan Node.js middleware allows an unauthenticated remote attacker to manipulate log entries. By injecting unescaped double quotes into HTTP headers, an attacker can cause log parsing tools to misinterpret subsequent log data, potentially forging log entries such as response status. This primarily impacts log integrity rather than enabling arbitrary code execution or system compromise.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.