Stefan Bühler of the lighthttpd project reports:

 Use after free if FAMMonitorDirectory fails
=============================================

 Description
-------------

If the "fam" is enabled:

    server.stat-cache-engine = "fam"

and there are directories reachable from configured doc roots and aliases on 
which FAMMonitorDirectory fails (probably depends on file system), a remote 
client could trigger a DoS.

This bug was found with the clang static analyzer.

 Detailed analysis
-------------------

If FAMMonitorDirectory fails, the memory intended to store the context is 
released; some lines below the "version" compoment of that context is read.
Reading invalid data doesn't matter, but the memory access could trigger a 
segfault.

 Affected versions
-------------------

All versions before 1.4.33.

 Patch
-------

See http://download.lighttpd.net/lighttpd/security/lighttpd-1.4.33_fix_fam_use_after_free.patch

 Fixed in
----------

1.4.x: http://redmine.lighttpd.net/projects/lighttpd/repository/revisions/2921
1.4.34: not released yet (http://www.lighttpd.net/)

 Solutions or workaround
-------------------------

Don't enable "fam".

 References
------------

[1] http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-XXXX (TBD)
[2] http://redmine.lighttpd.net/projects/lighttpd/repository/revisions/2921/diff/

 GPG signatures
----------------

* http://download.lighttpd.net/lighttpd/security/lighttpd-1.4.33_fix_fam_use_after_free.patch.asc
* http://download.lighttpd.net/lighttpd/security/lighttpd_sa_2013_03.txt.asc