+
+## insufficient checking for symlinks in srcdir path
+
+Ikiwiki did not check if path to the srcdir to contained a symlink. If an
+attacker had commit access to the directories in the path, they could
+change it to a symlink, causing ikiwiki to read and publish files that were
+not intended to be published. (But not write to them due to other checks.)
+
+In most configurations, this is not exploitable, because the srcdir is
+checked out of revision control, but the directories leading up to it are
+not. Or, the srcdir is a single subdirectory of a project in revision
+control (ie, `ikiwiki/doc`), and if the subdirectory were a symlink,
+ikiwiki would still typically not follow it.
+
+There are at least two configurations where this is exploitable:
+
+* If the srcdir is a deeper subdirectory of a project. For example if it is
+ `project/foo/doc`, an an attacker can replace `foo` with a symlink to a
+ directory containing a `doc` directory (not a symlink), then ikiwiki
+ would follow the symlink.
+* If the path to the srcdir in ikiwiki's configuration ended in "/",
+ and the srcdir is a single subdirectory of a project, (ie,
+ `ikiwiki/doc/`), the srcdir could be a symlink and ikiwiki would not
+ notice.
+
+This security hole was discovered on 26 November 2007 and fixed the same
+day with the release of ikiwiki 2.14. I recommend upgrading to this version
+if your wiki can be committed to by third parties. Alternatively, don't use
+a trailing slash in the srcdir, and avoid the (unusual) configurations that
+allow the security hole to be exploited.
+
+## javascript insertion via uris
+
+The htmlscrubber did not block javascript in uris. This was fixed by adding
+a whitelist of valid uri types, which does not include javascript.
+([[!cve CVE-2008-0809]]) Some urls specifyable by the meta plugin could also
+theoretically have been used to inject javascript; this was also blocked
+([[!cve CVE-2008-0808]]).
+
+This hole was discovered on 10 February 2008 and fixed the same day
+with the release of ikiwiki 2.31.1. (And a few subsequent versions..)
+A fix was also backported to Debian etch, as version 1.33.4. I recommend
+upgrading to one of these versions if your wiki can be edited by third
+parties.
+
+## Cross Site Request Forging
+
+Cross Site Request Forging could be used to constuct a link that would
+change a logged-in user's password or other preferences if they clicked on
+the link. It could also be used to construct a link that would cause a wiki
+page to be modified by a logged-in user. ([[!cve CVE-2008-0165]])
+
+These holes were discovered on 10 April 2008 and fixed the same day with
+the release of ikiwiki 2.42. A fix was also backported to Debian etch, as
+version 1.33.5. I recommend upgrading to one of these versions.
+
+## Cleartext passwords
+
+Until version 2.48, ikiwiki stored passwords in cleartext in the `userdb`.
+That risks exposing all users' passwords if the file is somehow exposed. To
+pre-emtively guard against that, current versions of ikiwiki store password
+hashes (using Eksblowfish).
+
+If you use the [[plugins/passwordauth]] plugin, I recommend upgrading to
+ikiwiki 2.48, installing the [[!cpan Authen::Passphrase]] perl module, and running
+`ikiwiki-transition hashpassword` to replace all existing cleartext passwords
+with strong blowfish hashes.
+
+You might also consider changing to [[plugins/openid]], which does not
+require ikiwiki deal with passwords at all, and does not involve users sending
+passwords in cleartext over the net to log in, either.
+
+## Empty password security hole
+
+This hole allowed ikiwiki to accept logins using empty passwords, to openid
+accounts that didn't use a password. It was introduced in version 1.34, and
+fixed in version 2.48. The [bug](http://bugs.debian.org/483770) was
+discovered on 30 May 2008 and fixed the same day. ([[!cve CVE-2008-0169]])
+
+I recommend upgrading to 2.48 immediatly if your wiki allows both password
+and openid logins.
+
+## Malformed UTF-8 DOS
+
+Feeding ikiwiki page sources containing certian forms of malformed UTF-8
+can cause it to crash. This can potentially be used for a denial of service
+attack.
+
+intrigeri discovered this problem on 12 Nov 2008 and a patch put in place
+later that day, in version 2.70. The fix was backported to testing as version
+2.53.3, and to stable as version 1.33.7.
+
+## Insufficient blacklisting in teximg plugin
+
+Josh Triplett discovered on 28 Aug 2009 that the teximg plugin's
+blacklisting of insecure TeX commands was insufficient; it could be
+bypassed and used to read arbitrary files. This was fixed by
+enabling TeX configuration options that disallow unsafe TeX commands.
+The fix was released on 30 Aug 2009 in version 3.1415926, and was
+backported to stable in version 2.53.4. If you use the teximg plugin,
+I recommend upgrading. ([[!cve CVE-2009-2944]])
+
+## javascript insertion via svg uris
+
+Ivan Shmakov pointed out that the htmlscrubber allowed `data:image/*` urls,
+including `data:image/svg+xml`. But svg can contain javascript, so that is
+unsafe.
+
+This hole was discovered on 12 March 2010 and fixed the same day
+with the release of ikiwiki 3.20100312.
+A fix was also backported to Debian etch, as version 2.53.5. I recommend
+upgrading to one of these versions if your wiki can be edited by third
+parties.