CVE-2008-5557: PHP

High severity, CVSS 10.0. EPSS: 7.4% chance of exploitation in the next 30 days.

Heap-based buffer overflow in ext/mbstring/libmbfl/filters/mbfilter_htmlent.c in the mbstring extension in PHP 4.3.0 through 5.2.6 allows context-dependent attackers to execute arbitrary code via a crafted string containing an HTML entity, which is not properly handled during Unicode conversion, related to the (1) mb_convert_encoding, (2) mb_check_encoding, (3) mb_convert_variables, and (4) mb_parse_str functions.

Affected products

• PHP PHP: version 4.3.0 only; version 4.3.1 only; version 4.3.2 only; version 4.3.3 only; version 4.3.4 only; version 4.3.5 only; …

Published 2008-12-23. Last modified 2026-06-16.