DocBook is a document markup language that can be transformed into other formats using a stylesheet. The default stylesheet provided with Red Hat Linux has an insecure option enabled.
The default stylesheet used when converting a DocBook document to multiple HTML files allows an untrusted document to write files outside of the current directory. This is because element identifiers (specified in the document) are used to form the names of the output files. If an untrusted document uses a full pathname as an identifier, it can cause that file to be written to -- as long as the user performing the conversion has write access. Updated docbook-utils packages are available that disable this feature and enable filenames to be generated based on the type of the element rather than its identifier. The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the name CAN-2002-0169 to this issue.