A security incident happend on the Fedora infrastructure. From the announcement mailing list:

On January 22, 2011 a Fedora contributor received an email from the Fedora
Accounts System indicating that his account details had been changed. He
contacted the Fedora Infrastructure Team indicating that he had received
the email, but had not made changes to his FAS account. The Infrastructure
Team immediately began investigating, and confirmed that the account had
indeed been compromised.

At this time, the Infrastructure Team has evidence that indicates the account
credentials were compromised externally, and that the Fedora Infrastructure was
not subject to any code vulnerability or exploit.

The account in question was not a member of any sysadmin or Release Engineering
groups. The following is a complete list of privileges on the account:
* SSH to fedorapeople.org (user permissions are very limited on this machine).
* Push access to packages in the Fedora SCM.
* Ability to perform builds and make updates to Fedora packages.

The Infrastructure Team took the following actions after being
notified of the issue:
1. Lock down access to the compromised account
2. Take filesystem snapshots of all systems the account had access to
(pkgs.fedoraproject.org, fedorapeople.org)
3. Audit SSH, FAS, Git, and Koji logs from the time of compromise to the
present
Here, we found that the attacker did:
* Change the account's SSH key in FAS
* Login to fedorapeople.org
The attacker did not:
* Push any changes to the Fedora SCM or access pkgs.fedoraproject.org in
any way
* Generate a koji cert or perform any builds
* Push any package updates

Based on the results of our investigation so far, we do not believe that any
Fedora packages or other Fedora contributor accounts were affected by this
compromise.

While the user in question had the ability to commit to Fedora SCM, the
Infrastructure Team does not believe that the compromised account was used to
do this, or cause any builds or updates in the Fedora build system. The
Infrastructure Team believes that Fedora users are in no way threatened by this
security breach and we have found no evidence that the compromise extended
beyond this single account.

As always, Fedora packagers are recommended to regularly review commits to
their packages and report any suspicious activity that they notice.

Fedora contributors are strongly encouraged to choose a strong FAS password.
Contributors should *NOT* use their FAS password on any other websites or
user accounts. If you receive an email from FAS notifying you of changes to
your account that you did not make, please contact the Fedora Infrastructure
team immediately via admin@fedoraproject.org.

We are still performing a more in-depth investigation and security audit and we
will post again if there are any material changes to our understanding.

--
Jared Smith
Fedora Project Leader