Sven Hoexter uploaded new packages for subversion which fixed the
following security problems:

  A NULL pointer dereference flaw exisits in mod_dav_svn, the Apache
  httpd module for the Subversion server, when listing of repositories
  (SVNListParentPath directive) is enabled. A remote user could use
  this flaw to cause denial of service (particular httpd thread crash).

  A server-side memory leak allows remote users to cause a denial
  of service (memory consumption and daemon outage or crash) via
  Subversion client "blame" or "log" operations, when the "-g" option
  (request to display additional merge history) is used.

For the lenny-backports distribution, the problems have been fixed in
version 1.6.12dfsg-4~bpo50+1.

For the upcoming stable version (squeeze) and the unstable distribution
(sid), these problems have been fixed in version 1.6.12dfsg-4.

Upgrade instructions

If you don't use pinning (see [1]) you have to update the package
manually via "apt-get -t lenny-backports install <packagelist>" with
the packagelist of your installed packages affected by this update.
[1] <>

We recommend to pin (in /etc/apt/preferences) the backports repository
to 200 so that new versions of installed  backports will be installed

  Package: *
  Pin: release a=lenny-backports
  Pin-Priority: 200