The authentication hook (mgs_hook_authz) in mod-gnutls 0.5.10 and earlier does not validate client certificates when “GnuTLSClientVerify require” is set, which allows remote attackers to spoof clients via a crafted certificate.
Source: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-2091
Reference (s):
- https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=578663
- DEBIAN:DSA-3177
- URL: http://www.debian.org/security/2015/dsa-3177
- GENTOO:GLSA-201709-04
- URL: https://security.gentoo.org/glsa/201709-04