CVE-2007-1661: Apple Mac OS X

Medium severity, CVSS 6.4. EPSS: 2.5% chance of exploitation in the next 30 days.

Perl-Compatible Regular Expression (PCRE) library before 7.3 backtracks too far when matching certain input bytes against some regex patterns in non-UTF-8 mode, which allows context-dependent attackers to obtain sensitive information or cause a denial of service (crash), as demonstrated by the "\X?\d" and "\P{L}?\d" patterns.

Affected products

• Apple Mac OS X: version 10.4.11 only
• Apple Mac OS X Server: version 10.4.11 only
• Pcre Perl-Compatible Regular Expression Library: up to and including 7.2; version 7.0 only; version 7.1 only

Published 2007-11-07. Last modified 2026-06-16.