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CVE-2026-6104

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

Description (CNA)

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.

Affected (CNA)

Vendor / productVersions
PHP Group / PHPaffected 8.4.* before 8.4.21; affected 8.5.* before 8.5.6

CWE

CWE-125

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.

redhat-SADP

A flaw was found in PHP. When an encoding name containing an embedded NUL byte is passed to `mb_convert_encoding()` or related mbstring functions, an out-of-bounds read of only 1 byte can occur due to the incorrect processing of string lengths. This issue can cause a denial of service or limited information disclosure.