USN-4966-1 fixed a vulnerability in libx11. This update provides the corresponding update for Ubuntu 14.04 ESM and Ubuntu 16.04 ESM.
Original advisory details:
It was discovered that libx11 incorrectly validated certain parameter lengths. A remote attacker could possibly use this issue to trick libx11 into emitting extra X protocol requests.
{ "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro", "binaries": [ { "binary_version": "2:1.6.2-1ubuntu2.1+esm2", "binary_name": "libx11-6" }, { "binary_version": "2:1.6.2-1ubuntu2.1+esm2", "binary_name": "libx11-6-dbg" }, { "binary_version": "2:1.6.2-1ubuntu2.1+esm2", "binary_name": "libx11-6-dbgsym" }, { "binary_version": "2:1.6.2-1ubuntu2.1+esm2", "binary_name": "libx11-6-udeb" }, { "binary_version": "2:1.6.2-1ubuntu2.1+esm2", "binary_name": "libx11-6-udeb-dbgsym" }, { "binary_version": "2:1.6.2-1ubuntu2.1+esm2", "binary_name": "libx11-data" }, { "binary_version": "2:1.6.2-1ubuntu2.1+esm2", "binary_name": "libx11-dev" }, { "binary_version": "2:1.6.2-1ubuntu2.1+esm2", "binary_name": "libx11-dev-dbgsym" }, { "binary_version": "2:1.6.2-1ubuntu2.1+esm2", "binary_name": "libx11-doc" }, { "binary_version": "2:1.6.2-1ubuntu2.1+esm2", "binary_name": "libx11-xcb-dev" }, { "binary_version": "2:1.6.2-1ubuntu2.1+esm2", "binary_name": "libx11-xcb-dev-dbgsym" }, { "binary_version": "2:1.6.2-1ubuntu2.1+esm2", "binary_name": "libx11-xcb1" }, { "binary_version": "2:1.6.2-1ubuntu2.1+esm2", "binary_name": "libx11-xcb1-dbg" }, { "binary_version": "2:1.6.2-1ubuntu2.1+esm2", "binary_name": "libx11-xcb1-dbgsym" } ] }
{ "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro", "binaries": [ { "binary_version": "2:1.6.3-1ubuntu2.2+esm1", "binary_name": "libx11-6" }, { "binary_version": "2:1.6.3-1ubuntu2.2+esm1", "binary_name": "libx11-6-dbg" }, { "binary_version": "2:1.6.3-1ubuntu2.2+esm1", "binary_name": "libx11-6-dbgsym" }, { "binary_version": "2:1.6.3-1ubuntu2.2+esm1", "binary_name": "libx11-6-udeb" }, { "binary_version": "2:1.6.3-1ubuntu2.2+esm1", "binary_name": "libx11-6-udeb-dbgsym" }, { "binary_version": "2:1.6.3-1ubuntu2.2+esm1", "binary_name": "libx11-data" }, { "binary_version": "2:1.6.3-1ubuntu2.2+esm1", "binary_name": "libx11-dev" }, { "binary_version": "2:1.6.3-1ubuntu2.2+esm1", "binary_name": "libx11-dev-dbgsym" }, { "binary_version": "2:1.6.3-1ubuntu2.2+esm1", "binary_name": "libx11-doc" }, { "binary_version": "2:1.6.3-1ubuntu2.2+esm1", "binary_name": "libx11-xcb-dev" }, { "binary_version": "2:1.6.3-1ubuntu2.2+esm1", "binary_name": "libx11-xcb-dev-dbgsym" }, { "binary_version": "2:1.6.3-1ubuntu2.2+esm1", "binary_name": "libx11-xcb1" }, { "binary_version": "2:1.6.3-1ubuntu2.2+esm1", "binary_name": "libx11-xcb1-dbg" }, { "binary_version": "2:1.6.3-1ubuntu2.2+esm1", "binary_name": "libx11-xcb1-dbgsym" } ] }