Global buffer over-read in mb_convert_encoding() with attacker-supplied encoding_CVE-2026-6104

6.3 / 10

MEDIUM

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:L/SC:L/SI:N/SA:L/RE:M/U:Amber

Description

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.

Basic Information

ID CVE-2026-6104

Source php

Published May 10, 2026 at 04:35

Affected Product

Vendor PHP Group

Product PHP

Version 8.4.*

Affected Versions PHP Group PHP 8.4.*
PHP Group PHP 8.5.*

CWE Classification

CWE-125

References

github.com /php/php-src/security/advisories/GHSA-74r9-qxhc-fx53

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    "published": "2026-05-10T04:35:17.328Z",
    "modified": "2026-05-10T04:35:17.328Z",
    "type": "cve",
    "title": "Global buffer over-read in mb_convert_encoding() with attacker-supplied encoding",
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