CVE-2026-6104

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 v3 9.1 CRITICAL

9.1^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.2

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/php/php-src/security/advisories/GHSA-74r9-qxhc-fx53	Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:php:php::::::::
	cpe:2.3:a:php:php::::::::

History

12 May 2026, 17:35

Type	Values Removed	Values Added
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 9.1
CPE		cpe:2.3:a:php:php::::::::
References	~~() https://github.com/php/php-src/security/advisories/GHSA-74r9-qxhc-fx53 -~~	() https://github.com/php/php-src/security/advisories/GHSA-74r9-qxhc-fx53 - Vendor Advisory
First Time		Php Php php

10 May 2026, 06:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-05-10 06:16

Updated : 2026-05-12 17:35

NVD link : CVE-2026-6104

Mitre link : CVE-2026-6104

CVE.ORG link : CVE-2026-6104

JSON object : View

Products Affected

php

php

CWE

CWE-125

Out-of-bounds Read

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