A vulnerability was found in capnproto. A malicious message could contain a far pointer pointing outside of the message. Cap'n Proto messages are broken into segments of continuous memory. A far pointer points from one segment into another, indicating both the segment number and an offset within that segment. If a malicious far pointer contained an offset large enough to overflow the pointer arithmetic (wrapping around to the beginning of memory), then it would escape bounds checking, in part because the compiler would elide half of the bounds check as an optimization. External References: https://github.com/sandstorm-io/capnproto/blob/master/security-advisories/2017-04-17-0-apple-clang-elides-bounds-check.md Upstream patch: https://github.com/sandstorm-io/capnproto/commit/52bc956459a5e83d7c31be95763ff6399e064ae4
Created capnproto tracking bugs for this issue: Affects: epel-7 [bug 1443628] Affects: fedora-all [bug 1443629]