A security issue affects the following Ubuntu releases:
This advisory also applies to the corresponding versions of Kubuntu, Edubuntu, and Xubuntu.
The problem can be corrected by upgrading your system to the following package versions:
Ubuntu 9.04: libnss3-1d 3.12.6-0ubuntu0.9.04.1
After a standard system upgrade you need to restart your session to effect the necessary changes.
USN-927-1 fixed vulnerabilities in NSS on Ubuntu 9.10. This update provides the corresponding updates for Ubuntu 9.04.
Original advisory details:
Marsh Ray and Steve Dispensa discovered a flaw in the TLS and SSLv3 protocols. If an attacker could perform a man in the middle attack at the start of a TLS connection, the attacker could inject arbitrary content at the beginning of the user's session. This update adds support for the new new renegotiation extension and will use it when the server supports it.