Oracle Linux: CVE-2017-7805: ELSA-2017-2832: nss security update (IMPORTANT) (Multiple Advisories)

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.
A use-after-free flaw was found in the TLS 1.2 implementation in the NSS library when client authentication was used. A malicious client could use this flaw to cause an application compiled against NSS to crash or, potentially, execute arbitrary code with the permission of the user running the application.