The ospf_flood function in ospf_flood.c in ospfd in Quagga before 0.99.19 allows remote attackers to cause a denial of service (daemon crash) via an invalid Link State Advertisement (LSA) type in an IPv4 Link State Update message.
https://www.cert.fi/en/reports/2011/vulnerability539178.html
http://www.quagga.net/download/quagga-0.99.19.changelog.txt
http://www.kb.cert.org/vuls/id/668534
http://www.debian.org/security/2011/dsa-2316
http://security.gentoo.org/glsa/glsa-201202-02.xml
http://secunia.com/advisories/48106
http://secunia.com/advisories/46274
http://secunia.com/advisories/46139
http://rhn.redhat.com/errata/RHSA-2012-1259.html
http://rhn.redhat.com/errata/RHSA-2012-1258.html
http://lists.opensuse.org/opensuse-security-announce/2011-12/msg00009.html
http://lists.opensuse.org/opensuse-security-announce/2011-10/msg00010.html
http://lists.opensuse.org/opensuse-security-announce/2011-10/msg00007.html
http://lists.opensuse.org/opensuse-security-announce/2011-09/msg00027.html
http://code.quagga.net/?p=quagga.git%3Ba=commit%3Bh=6b161fc12a15aba8824c84d1eb38e529aaf70769