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CVE-2026-6104

Global buffer over-read in mb_convert_encoding() with attacker-supplied encoding

Published: May 10, 2026Updated: Jul 24, 2026 Sources: CVE List NVDCWE-125
9.1CRITICAL
NVD MITRE
EPSS Score
0.5%
Top 61.8%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
OpenVAS

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:HI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:NIntegrity
None
A:HAvailability
High
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Weaknesses

CWE-125

Affected Products

PHP Group
oss-projectaka pear, php
PHPLibraryLibrary
OSS Libraries
php
oss-project·USaka pecl, php language, pear
phpDev Tool
OSS Libraries / generic-library

Exploitability

Official Patch Available
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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

1 technique
Collection
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References

https://github.com/php/php-src/security/advisories/GHSA-74r9-qxhc-fx53
github.com
https://access.redhat.com/errata/RHSA-2026:22649
access.redhat.com
https://access.redhat.com/security/cve/CVE-2026-6104
access.redhat.com
and 2 more references View all →

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