Debian Security Advisory 1576-2 – Matt Zimmerman discovered that entries in ~/.ssh/authorized_keys with options (such as “no-port-forwarding” or forced commands) were ignored by the new ssh-vulnkey tool introduced in openssh 1:4.3p2-9etch1 (see DSA 1576-1). This could cause some compromised keys not to be listed in ssh-vulnkey’s output.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/66473/dsa-1576-2.txt
Source: https://packetstormsecurity.com/files/66473/Debian-Linux-Security-Advisory-1576-2.html