Perl-Compatible Regular Expression (PCRE) library before 6.7 allows context-dependent attackers to cause a denial of service (error or crash) via a regular expression that involves a "malformed POSIX character class", as demonstrated via an invalid character after a [[ sequence.
The Perl_reg_numbered_buff_fetch function in Perl 5.10.0, 5.12.0, 5.14.0, and other versions, when running with debugging enabled, allows context-dependent attackers to cause a denial of service (assertion failure and application exit) via crafted input that is not properly handled when using certain regular expressions, as demonstrated by causing SpamAssassin and OCSInventory to crash.
Off-by-one error in the bzinflate function in Bzip2.xs in the Compress-Raw-Bzip2 module before 2.018 for Perl allows context-dependent attackers to cause a denial of service (application hang or crash) via a crafted bzip2 compressed stream that triggers a buffer overflow, a related issue to CVE-2009-1391.