It was discovered that libXfont incorrectly followed symlinks when opening font files. A local unprivileged user could use this issue to cause the X server to access arbitrary files, including special device files.
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{ "availability": "No subscription required", "binaries": [ { "binary_version": "1:1.5.1-1ubuntu0.16.04.4", "binary_name": "libxfont1" }, { "binary_version": "1:1.5.1-1ubuntu0.16.04.4", "binary_name": "libxfont1-dbg" }, { "binary_version": "1:1.5.1-1ubuntu0.16.04.4", "binary_name": "libxfont1-dbgsym" }, { "binary_version": "1:1.5.1-1ubuntu0.16.04.4", "binary_name": "libxfont1-dev" }, { "binary_version": "1:1.5.1-1ubuntu0.16.04.4", "binary_name": "libxfont1-dev-dbgsym" }, { "binary_version": "1:1.5.1-1ubuntu0.16.04.4", "binary_name": "libxfont1-udeb" }, { "binary_version": "1:1.5.1-1ubuntu0.16.04.4", "binary_name": "libxfont1-udeb-dbgsym" } ] }
{ "availability": "No subscription required", "binaries": [ { "binary_version": "1:2.0.1-3~ubuntu16.04.3", "binary_name": "libxfont-dev" }, { "binary_version": "1:2.0.1-3~ubuntu16.04.3", "binary_name": "libxfont2" }, { "binary_version": "1:2.0.1-3~ubuntu16.04.3", "binary_name": "libxfont2-dbgsym" }, { "binary_version": "1:2.0.1-3~ubuntu16.04.3", "binary_name": "libxfont2-udeb" }, { "binary_version": "1:2.0.1-3~ubuntu16.04.3", "binary_name": "libxfont2-udeb-dbgsym" } ] }