{"id":"CVE-2026-53163","summary":"locking/rtmutex: Skip remove_waiter() when waiter is not enqueued","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nlocking/rtmutex: Skip remove_waiter() when waiter is not enqueued\n\nsyzbot triggered the following splat in remove_waiter() via\nFUTEX_CMP_REQUEUE_PI:\n\n  KASAN: null-ptr-deref in range [0x0000000000000a88-0x0000000000000a8f]\n   class_raw_spinlock_constructor\n   remove_waiter+0x159/0x1200 kernel/locking/rtmutex.c:1561\n   rt_mutex_start_proxy_lock+0x103/0x120\n   futex_requeue+0x10e4/0x20d0\n   __x64_sys_futex+0x34f/0x4d0\n\ntask_blocks_on_rt_mutex() does not arm the waiter upon deadlock detection,\nleaving waiter-\u003etask nil, where 3bfdc63936dd (\"rtmutex: Use waiter::task instead\nof current in remove_waiter()\") made this fatal.\n\nFurthermore, rt_mutex_start_proxy_lock() should not be calling into remove_waiter()\nupon a successfully grabbing the rtmutex. 1a1fb985f2e2 (\"futex: Handle early deadlock\nreturn correctly\"), moved the remove_waiter() out of __rt_mutex_start_proxy_lock()\n(where 'ret' was only ever 0 or \u003c 0) into the wrapper. Tighten this check to\naccount for try_to_take_rt_mutex().","modified":"2026-07-09T04:44:19.741527426Z","published":"2026-06-25T08:38:44.108Z","related":["CGA-3p57-p73j-cm9r"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53163.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/40a25d59e85b3c8709ac2424d44f65610467871e"},{"type":"WEB","url":"https://git.kernel.org/stable/c/4afda3a1da02129568a3a2f1898aa13e6763bcba"},{"type":"WEB","url":"https://git.kernel.org/stable/c/55363fa0a04524d11efeaadee734d2db1756ed27"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5799f9bd7fee40370b93ab1ddf001cdc7017c14d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6707d7e0b71748cb3cd95bad81dae5fe1b3c8f48"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a388e3dfaf9538a680de5ed43a8ebb5dd45b6e53"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53163.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53163"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"d8cce4773c2b23d819baf5abedc62f7b430e8745"},{"fixed":"4afda3a1da02129568a3a2f1898aa13e6763bcba"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"8a1fc8d698ac5e5916e3082a0f74450d71f9611f"},{"fixed":"6707d7e0b71748cb3cd95bad81dae5fe1b3c8f48"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"6d52dfcb2a5db86e346cf51f8fcf2071b8085166"},{"fixed":"5799f9bd7fee40370b93ab1ddf001cdc7017c14d"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"3fb7394a837740770f0d6b4b30567e60786a63f2"},{"fixed":"a388e3dfaf9538a680de5ed43a8ebb5dd45b6e53"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"88614876370aac8ad1050ad785a4c095ba17ac11"},{"fixed":"55363fa0a04524d11efeaadee734d2db1756ed27"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"3bfdc63936dd4773109b7b8c280c0f3b5ae7d349"},{"fixed":"40a25d59e85b3c8709ac2424d44f65610467871e"}]}],"versions":["v6.1.176","v6.1.175","v6.6.143","v6.6.142","v6.6.141","v6.6.140","v6.12.94","v6.12.93","v6.12.92","v6.12.91","v6.12.90","v6.12.89","v6.12.88","v6.12.87","v6.12.86","v6.18.35","v6.18.34","v6.18.33","v6.18.32","v6.18.31","v6.18.30","v6.18.29","v6.18.28","v6.18.27","v7.0.12","v7.0.11","v7.0.10","v7.0.9","v7.0.8","v7.0.7","v7.0.6","v7.0.5","v7.0.4"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53163.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.1.175"},{"fixed":"6.1.177"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.6.140"},{"fixed":"6.6.144"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.12.86"},{"fixed":"6.12.95"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.18.27"},{"fixed":"6.18.36"}]},{"type":"ECOSYSTEM","events":[{"introduced":"7.0.4"},{"fixed":"7.0.13"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53163.json"}}],"schema_version":"1.7.5"}