CVE-2026-6104 Affecting php8.4 package, versions <8.4.11-1ubuntu1.2


Severity

Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.47% (38th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • Snyk IDSNYK-UBUNTU2510-PHP84-16654858
  • published25 May 2026
  • disclosed10 May 2026

Introduced: 10 May 2026

CVE-2026-6104  (opens in a new tab)

How to fix?

Upgrade Ubuntu:25.10 php8.4 to version 8.4.11-1ubuntu1.2 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream php8.4 package and not the php8.4 package as distributed by Ubuntu. See How to fix? for Ubuntu:25.10 relevant fixed versions and status.

In PHP versions 8.4.* before 8.4.21 and 8.5.* before 8.5.6, when an encoding name containing an embedded NUL byte is passed to mb_convert_encoding() or related mbstring functions, the code incorrectly assumes that when strncasecmp() returns 0 it means the strings have the same length. This can lead to out-of-bounds read of global memory, potentially causing a crash or information disclosure or crash. Affected functions include mb_convert_encoding(), mb_detect_encoding(), mb_convert_variables(), and mb_detect_order(), as well as the mbstring.detect_order and mbstring.http_output INI settings.

CVSS Base Scores

version 3.1