{"id":"CVE-2026-89540","revision":"1e0223bd05974283b425fce0c578ca41","records":[{"revision":"1e0223bd05974283b425fce0c578ca41","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-89540","aliases":[],"title":"sunrpc: init gssp_lock before publishing proc entry","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsunrpc: init gssp_lock before publishing proc entry\n\ncreate_use_gss_proxy_proc_entry() publishes /proc/net/rpc/use-gss-proxy\nvia proc_create_data() before init_gssp_clnt() runs mutex_init() on\nsn->gssp_lock.  Once the dentry is linked under proc_subdir_lock it is\nimmediately reachable from userspace, so a write that lands in the\nwindow drives set_gssp_clnt() into mutex_lock() on a zero-initialized\nstruct mutex.\n\n    create_use_gss_proxy_proc_entry(net)\n      proc_create_data(\"use-gss-proxy\", ...)   /* dentry live */\n      init_gssp_clnt(sn)\n        mutex_init(&sn->gssp_lock)             /* too late */\n\n    write_gssp()\n      set_gssp_clnt(net)\n        mutex_lock(&sn->gssp_lock)             /* uninitialized */\n        gssp_rpc_create(...)\n        sn->gssp_clnt = clnt\n        mutex_unlock(&sn->gssp_lock)\n\nThe window spans only the two statements between proc_create_data()\nreturning and init_gssp_clnt(), so a writer reaches it only if the\nregistering thread is preempted there while another task is already\nopening the freshly published file.  register_pernet_subsys() runs in\npreemptible context under pernet_ops_rwsem, so that preemption is\npossible, and the window widens on auth_rpcgss module load, when the\nproc entry is created for every live net namespace whose tasks are\nalready running.  A writer that wins the race locks a zero-filled\nstruct mutex.  On CONFIG_DEBUG_MUTEXES the missing magic value trips a\n\"lock used without init\" splat; on a production kernel the fast path\nacquires the lock via CMPXCHG(owner, 0, current).  In the latter case\na second writer that arrives before init_gssp_clnt() re-zeroes owner\ncan enter set_gssp_clnt() concurrently, shut down the first writer's\nclnt while it is still in use, and leak the loser's clnt.\n\nFix by initializing sn->gssp_lock in sunrpc_init_net() so its lifetime\nmatches the sunrpc_net it lives in.  sn->gssp_clnt is already NULL from\nthe kzalloc that backs net_generic storage, so the lazy helper is no\nlonger needed; drop init_gssp_clnt(), its prototype, and the call from\ncreate_use_gss_proxy_proc_entry().  sunrpc.ko is a build-time\ndependency of auth_rpcgss.ko, so sunrpc_init_net() has always run on\nevery netns before any auth_gss pernet init can publish the proc\nentry.","state":0,"publishedAt":"2026-09-11T19:44:17.44+00:00","modifiedAt":"2026-10-19T08:48:31.93+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/sunrpc/auth_gss/gss_rpc_upcall.c\",\n                        \"net/sunrpc/auth_gss/gss_rpc_upcall.h\",\n                        \"net/sunrpc/auth_gss/svcauth_gss.c\",\n                        \"net/sunrpc/sunrpc_syms.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"030d794bf49855f5e2a9e8dfbfad34211d1eb08b\",\n                            \"lessThan\": \"159a4fab7170badd6c4a553aef81cac079d6f4ee\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"030d794bf49855f5e2a9e8dfbfad34211d1eb08b\",\n                            \"lessThan\": \"b3526ae3351968f6726bcbe25d8d09973ad79109\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"030d794bf49855f5e2a9e8dfbfad34211d1eb08b\",\n                            \"lessThan\": \"7f5bcdc8da15077ebe846c2756a5a17741021410\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"030d794bf49855f5e2a9e8dfbfad34211d1eb08b\",\n                            \"lessThan\": \"89c8e0733e8c46b7973503f15b1b31a8587d8030\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"030d794bf49855f5e2a9e8dfbfad34211d1eb08b\",\n                            \"lessThan\": \"f15b87521168c2a92cb1931f532cba422f856f01\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"030d794bf49855f5e2a9e8dfbfad34211d1eb08b\",\n                            \"lessThan\": \"edeefb111d6181a4aa278f415b005efe284b9489\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"030d794bf49855f5e2a9e8dfbfad34211d1eb08b\",\n                            \"lessThan\": \"3f019571928b269feebcff59926ec13294215e0e\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"030d794bf49855f5e2a9e8dfbfad34211d1eb08b\",\n                            \"lessThan\": \"5ce1ed6159731a41fdd0b03eedbed4e147036a5a\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/sunrpc/auth_gss/gss_rpc_upcall.c\",\n                        \"net/sunrpc/auth_gss/gss_rpc_upcall.h\",\n                        \"net/sunrpc/auth_gss/svcauth_gss.c\",\n                        \"net/sunrpc/sunrpc_syms.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"3.10\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"3.10\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.10.270\",\n                            \"lessThanOrEqual\": \"5.10.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.221\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.188\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.157\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.109\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.50\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.4\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/159a4fab7170badd6c4a553aef81cac079d6f4ee","https://git.kernel.org/stable/c/b3526ae3351968f6726bcbe25d8d09973ad79109","https://git.kernel.org/stable/c/7f5bcdc8da15077ebe846c2756a5a17741021410","https://git.kernel.org/stable/c/89c8e0733e8c46b7973503f15b1b31a8587d8030","https://git.kernel.org/stable/c/f15b87521168c2a92cb1931f532cba422f856f01","https://git.kernel.org/stable/c/edeefb111d6181a4aa278f415b005efe284b9489","https://git.kernel.org/stable/c/3f019571928b269feebcff59926ec13294215e0e","https://git.kernel.org/stable/c/5ce1ed6159731a41fdd0b03eedbed4e147036a5a"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89540","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-89540","identifiers":["CVE-2026-89540"]},"retained":false,"historicalAffected":[]}],"coverage":[]}