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CVE-2026-89708: Linux

9.8

CVSS 3.1

Няма данни

Вероятност да бъде експлоатирана в следващите 30 дни (EPSS)

Няма потвърждение

Атакува се

Няма данни

Време до експлоатация

Атакува се по мрежата, без особени условия, без вход и без действие от потребителя.

  • Експлоатация: няма данни за експлоатация
  • Атаката може да се автоматизира

Описание

Оригинално описание

In the Linux kernel, the following vulnerability has been resolved: nfsd: RCU-protect cl_cb_session to fix use-after-free on session teardown After a DESTROY_SESSION the per-session teardown path can free a session while rpciod still holds an inflight callback rpc_task that dereferences clp->cl_cb_session. nfsd4_probe_callback_sync() flushes cl_callback_wq, but once nfsd4_run_cb_work() has called rpc_call_async() the rpc_task lives on rpciod; flushing the workqueue does not wait for it. rpc_shutdown_client() does drain rpciod tasks, but uses a 1-second wait_event_timeout — tasks stuck in rpc_delay() (e.g. 2-second NFS4ERR_DELAY retries) can outlive the drain. destroy path rpciod ------------ ------ unhash_session(ses) nfsd4_probe_callback_sync(clp) flush_workqueue(cl_callback_wq) /* returns; rpc_task still live */ nfsd4_put_session_locked(ses) free_session(ses) -> kfree(ses) nfsd4_cb_sequence_done() reads cb_clp->cl_cb_session /* freed slab */ A second window exists in nfsd4_process_cb_update(). When __nfsd4_find_backchannel() returns NULL because unhash_session() has already removed the destroyed session from cl_sessions, setup_callback_client() takes the v4.1 early return so clp->cl_cb_session = ses never fires and the field retains a pointer to the about-to-be-freed session. Fix both by converting cl_cb_session to an RCU-protected pointer: - Move the cl_cb_session = ses assignment in setup_callback_client() to after rpc_create() succeeds, so it is only published when a working backchannel exists. Clear cl_cb_session on the error return in nfsd4_process_cb_update(). Both stores use rcu_assign_pointer(). - Annotate cl_cb_session with __rcu. All rpciod-side readers use rcu_read_lock()/rcu_dereference() and check for NULL, bailing to

Засегнати продукти

  • Linux Linux: dcbeaa68dbbdacbbb330a86c7fc95a28473fc209 преди 2775ec1d617e665eab71ce0f13ab1f7959713a2b; dcbeaa68dbbdacbbb330a86c7fc95a28473fc209 преди f164eb52b6f3cbf40f07fe379f9f421f88e02f76; dcbeaa68dbbdacbbb330a86c7fc95a28473fc209 преди 13bdd486c3aad4fc19e6d8b9c3556a4b4c190b25; dcbeaa68dbbdacbbb330a86c7fc95a28473fc209 преди 01c5d5f58a5db9b0ee5afba2e49d3157788687b2
  • Linux Linux: 2.6.38; преди 2.6.38; 6.12.111 до 6.12.*; 6.18.50 до 6.18.*; 7.2.4 до 7.2.*; 7.3 до *

История

  • 11 септември 2026 Публикувано

Други уязвимости в Linux Linux

Първоизточници

CVE-2026-89708: Linux | freedomonline.bg