Using the Address Sanitizer tool, security researcher Atte Kettunen from OUSPG discovered a buffer overflow during interaction with the Web Audio buffer for playback because of an error in the the amount of allocated memory for buffers. This leads to a potentially exploitable crash with some audio content.
In general this flaw cannot be exploited through email in the Thunderbird product because scripting is disabled, but is potentially a risk in browser or browser-like contexts.
Red Hat would like to thank the Mozilla project for reporting this issue. Upstream acknowledges Atte Kettunen as the original reporter.
This issue does not affect the version of thunderbird as shipped with Red Hat Enterprise Linux 5 and 6, or the version of firefox as shipped with Red Hat Enterprise Linux 5, 6, and 7.