September 02, 2014
The recent release of Firefox 32 fixes another interesting image parsing issue found by american fuzzy lop: following a refactoring of memory management code, the past few versions of the browser ended up using uninitialized memory for certain types of truncated images, which is easily measurable with a simple <canvas> + toDataURL() harness that examines all the fuzzer-generated test cases. In general, problems like that may leak secrets across web origins, or more prosaically, may help attackers bypass security measures such as ASLR. For a slightly more detailed discussion, check out this post. Here's a short proof-of-concept that should work if you haven't updated to 32 yet: 1045977. Several more should be coming soon.