CVE-2017-7805

During TLS 1.2 exchanges, handshake hashes are generated which point to a
message buffer. This saved data is used for later messages but in some
cases, the handshake transcript can exceed the space available in the
current buffer, causing the allocation of a new buffer. This leaves a
pointer pointing to the old, freed buffer, resulting in a use-after-free
when handshake hashes are then calculated afterwards. This can result in a
potentially exploitable crash. This vulnerability affects Firefox < 56,
Firefox ESR < 52.4, and Thunderbird < 52.4.

Bugs

• <https://bugzilla.mozilla.org/show_bug.cgi?id=1377618&gt;