CVE-2026-89540

CVE CVE-2026-89540EUVD EUVD-2026-76451Veröffentlicht 2026-09-11T19:44:17.000ZZuletzt geändert 2026-09-14T12:00:47.000ZCVSS 7.8

Was das Advisory beschreibt

In the Linux kernel, the following vulnerability has been resolved: sunrpc: init gssp_lock before publishing proc entry create_use_gss_proxy_proc_entry() publishes /proc/net/rpc/use-gss-proxy via proc_create_data() before init_gssp_clnt() runs mutex_init() on sn->gssp_lock. Once the dentry is linked under proc_subdir_lock it is immediately reachable from userspace, so a write that lands in the window drives set_gssp_clnt() into mutex_lock() on a zero-initialized struct mutex. create_use_gss_proxy_proc_entry(net) proc_create_data("use-gss-proxy", ...) /* dentry live */ init_gssp_clnt(sn) mutex_init(&sn->gssp_lock) /* too late */ write_gssp() set_gssp_clnt(net) mutex_lock(&sn->gssp_lock) /* uninitialized */ gssp_rpc_create(...) sn->gssp_clnt = clnt mutex_unlock(&sn->gssp_lock) The window spans only the two statements between proc_create_data() returning and init_gssp_clnt(), so a writer reaches it only if the registering thread is preempted there while another task is already opening the freshly published file. register_pernet_subsys() runs in preemptible context under pernet_ops_rwsem, so that preemption is possible, and the window widens on auth_rpcgss module load, when the proc entry is created for every live net namespace whose tasks are already running. A writer that wins the race locks a zero-filled struct mutex. On CONFIG_DEBUG_MUTEXES the missing magic value trips a "lock used without init" splat; on a production kernel the fast path acquires the lock via CMPXCHG(owner, 0, current). In the latter case a second writer that arrives before init_gssp_clnt() re-zeroes owner can enter set_gssp_clnt() concurrently, shut down the first writer's clnt while it is still in use, and leak the loser's clnt. Fix by initializing sn->gssp_lock in sunrpc_init_net() so its lifetime matches the sunrpc_net it lives in. sn->gssp_clnt is already NULL from the kzalloc that backs net_generic storage, so the lazy helper is no longer needed; drop init_gssp_clnt(), its prototype, and the call from create_use_gss_proxy_proc_entry(). sunrpc.ko is a build-time dependency of auth_rpcgss.ko, so sunrpc_init_net() has always run on every netns before any auth_gss pernet init can publish the proc entry.

Quelle: EUVD (ENISA), im Wortlaut der Meldung.

Produkte, die das Advisory nennt

Diese Angaben stammen aus der Meldung selbst, nicht aus einer Prüfung durch uns.

• Linux — Linux patch: 6.6.157; 030d794bf49855f5e2a9e8dfbfad34211d1eb08b <159a4fab7170badd6c4a553aef81cac079d6f4ee; patch: 5.15.221; 030d794bf49855f5e2a9e8dfbfad34211d1eb08b <b3526ae3351968f6726bcbe25d8d09973ad79109; 030d794bf49855f5e2a9e8dfbfad34211d1eb08b <3f019571928b269feebcff59926ec13294215e0e; patch: 7.3-rc1; 3.10; 030d794bf49855f5e2a9e8dfbfad34211d1eb08b <5ce1ed6159731a41fdd0b03eedbed4e147036a5a; patch: 6.18.50; 030d794bf49855f5e2a9e8dfbfad34211d1eb08b <edeefb111d6181a4aa278f415b005efe284b9489; patch: 7.2.4; patch: 0; 030d794bf49855f5e2a9e8dfbfad34211d1eb08b <f15b87521168c2a92cb1931f532cba422f856f01; patch: 6.12.109; 030d794bf49855f5e2a9e8dfbfad34211d1eb08b <89c8e0733e8c46b7973503f15b1b31a8587d8030; 030d794bf49855f5e2a9e8dfbfad34211d1eb08b <7f5bcdc8da15077ebe846c2756a5a17741021410; patch: 6.1.188; patch: 5.10.270

Die genannten Versionen sind die Angabe der Meldung. Patchlage vergleicht keine Versionsnummern und leitet aus ihnen keine Aussage ab — welche Version installiert ist, muss ein Mensch nachsehen.

Im Produktkatalog geführt

Für diese Produkte kann ein Bestand in Patchlage erfasst werden. Ein Advisory dazu erscheint am Morgen danach im Lagebericht.

• Linux — Linux

Patchlage meldet Treffer und Verdachtsfälle. Zu allem anderen sagt dieses System nichts — weder diese Seite noch der Lagebericht behauptet je, dass ein Bestand sicher ist.