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
https://access.redhat.com/errata/RHSA-2026:22649
https://access.redhat.com/security/cve/CVE-2026-6104
https://bugzilla.redhat.com/show_bug.cgi?id=2468573
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-6104.json

Configurations

Configuration 1 (hide)

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

History

No history.

Information

Published : 2026-05-10 06:16

Updated : 2026-07-24 08:10

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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encoding name containing an embedded NUL byte is passed to mb_convert_encoding() or related mbstring functions, the code incorrectly assumes that when\u00a0strncasecmp()\u00a0returns 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.\u00a0Affected 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."}, {"lang": "es", "value": "En versiones de PHP 8.4.* anteriores a 8.4.21 y 8.5.* anteriores a 8.5.6, cuando un nombre de codificaci\u00f3n que contiene un byte NUL incrustado se pasa a mb_convert_encoding() o funciones mbstring relacionadas, el c\u00f3digo asume incorrectamente que cuando strncasecmp() devuelve 0 significa que las cadenas tienen la misma longitud. Esto puede llevar a una lectura fuera de l\u00edmites de la memoria global, lo que podr\u00eda causar un fallo o revelaci\u00f3n de informaci\u00f3n o un fallo. Las funciones afectadas incluyen mb_convert_encoding(), mb_detect_encoding(), mb_convert_variables() y mb_detect_order(), as\u00ed como las configuraciones INI mbstring.detect_order y mbstring.http_output."}], "lastModified": "2026-07-24T08:10:00.150", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:php:php:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "BA663C03-392C-41CC-BD11-4A1245203C42", "versionEndExcluding": "8.4.21", "versionStartIncluding": "8.4.0"}, {"criteria": "cpe:2.3:a:php:php:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "6101DA12-5AA1-4882-A52A-61FB74254F9A", "versionEndExcluding": "8.5.6", "versionStartIncluding": "8.5.0"}], "operator": "OR"}]}], "sourceIdentifier": "security@php.net"}