Debian Security Advisory 1556-2 – An editorial mistake resulted in DSA-1556-1 not correctly applying the required change, making it ineffective. This DSA has been reissued as DSA-1556-2. It has been discovered that the Perl interpreter may encounter a buffer overflow condition when compiling certain regular expressions containing Unicode characters. This also happens if the offending characters are contained in a variable reference protected by the Q E quoting construct. When encountering this condition, the Perl interpreter typically crashes, but arbitrary code execution cannot be ruled out.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/65867/dsa-1556-2.txt
Source: https://packetstormsecurity.com/files/65867/Debian-Linux-Security-Advisory-1556-2.html