Description: There exists a denial of service problem in libxml's UTF-8 decoding functions. The xmlCurrentChar() function does not check UTF-8 correctness and certain multibyte combinations can cause the library to enter an infinite loop and hang, consuming system resources. It is strongly recommended to upgrade if your application accepts arbitrary xml user input.

Provided by: The issue was originally discovered at Google by Brad Fitzpatrick and further investigated by Peter Valchev and Will Drewry. Patch and debugging by Daniel Veillard (libxml).

Acknowledgements:

Red Hat would like to thank the Google Security Team for responsibly disclosing this issue.

Buffer overflow in the polymorphic opcode support in the Regular Expression Engine (regcomp.c) in Perl 5.8 allows context-dependent attackers to execute arbitrary code by switching from byte to Unicode (UTF) characters in a regular expression.

Heap-based buffer overflow in libmpdemux/aviheader.c in MPlayer 1.0rc1 and earlier allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via a .avi file with certain large "indx truck size" and nEntriesInuse values, and a certain wLongsPerEntry value.

Dirk Mueller reported an off by one buffer overflow flaw in the way QT parses certain unicode strings.

To quote Dirk:

Ive found a off-by-one buffer overflow in QUtf8Decoder::toUnicode(). It is not exploitable with Qt 4.x or above because there is an additional QChar(0) being allocated in QString, however it is still a bug there, as the array returned by utf16() etc is no longer terminated properly.

Emacs 21 allows user-assisted attackers to cause a denial of service (crash) via certain crafted images, as demonstrated via a GIF image in vm mode, related to image size calculation.