CVE-2012-4388: Canonical Ubuntu Linux

Medium severity, CVSS 4.3. EPSS: 4.2% chance of exploitation in the next 30 days.

The sapi_header_op function in main/SAPI.c in PHP 5.4.0RC2 through 5.4.0 does not properly determine a pointer during checks for %0D sequences (aka carriage return characters), which allows remote attackers to bypass an HTTP response-splitting protection mechanism via a crafted URL, related to improper interaction between the PHP header function and certain browsers, as demonstrated by Internet Explorer and Google Chrome. NOTE: this vulnerability exists because of an incorrect fix for CVE-2011-1398.

Affected products

• Canonical Ubuntu Linux: version 8.04 only; version 10.04 only; version 11.04 only; version 11.10 only; version 12.04 only
• Debian Debian Linux: version 6.0 only
• PHP PHP: from 5.3.0, before 5.3.11 (fixed in 5.3.11); version 5.4.0 only

Published 2012-09-07. Last modified 2026-06-16.