{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64262","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-07-19T15:36:31.774Z","datePublished":"2026-07-25T08:49:12.599Z","dateUpdated":"2026-08-17T04:52:15.740Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-17T04:52:15.740Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nfuse-uring: end fuse_req on io-uring cancel task work\n\nWhen io_uring delivers task work with tw.cancel set (PF_EXITING,\nPF_KTHREAD fallback, or percpu_ref_is_dying on the ring context),\nfuse_uring_send_in_task() takes the cancel branch, assigns\n-ECANCELED, and falls through to fuse_uring_send(). That path only\nflips the entry to FRRS_USERSPACE and completes the io_uring cmd;\nit never discharges the ring entry's owning reference to the\nfuse_req that fuse_uring_add_req_to_ring_ent() handed it at\ndispatch time.\n\n    fuse_uring_send_in_task()\n      tw.cancel == true\n        err = -ECANCELED\n      fuse_uring_send(ent, cmd, err, issue_flags)\n        ent->state = FRRS_USERSPACE\n        list_move(&ent->list, &queue->ent_in_userspace)\n        ent->cmd = NULL\n        io_uring_cmd_done(-ECANCELED)\n        /* ent->fuse_req still set, req still hashed */\n\nThe fuse_req stays linked on fpq->processing[hash] and\nfuse_request_end() is never invoked. The originating syscall\nthread blocks in D-state in request_wait_answer() until\nfuse_abort_conn() runs, which can be the entire connection\nlifetime. For FR_BACKGROUND requests fc->num_background is never\ndecremented either, so repeated cancels inflate the counter until\nmax_background is hit and all later background ops stall. tw.cancel does\nnot imply a connection abort (e.g. a single io_uring worker thread exits\nwhile the fuse connection stays up), so this cannot be left for\nfuse_abort_conn() to clean up.\n\nEnding the req but still routing the entry through fuse_uring_send()\nis not enough: that leaves a req-less entry on ent_in_userspace, and\nent_list_request_expired() dereferences ent->fuse_req unconditionally\non the head of that list, which would then NULL-deref.\n\nFix the cancel branch to release the entry directly. Remove it from the\nqueue, complete the io_uring cmd, end the fuse_req, free the entry, and\ndrop its queue_refs (waking the teardown waiter if it was the last)."}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/fuse/dev_uring.c"],"versions":[{"version":"c2c9af9a0b13261c36909036057a116f2edb5e1a","lessThan":"bb476ef8e1027a9d509fbaaf81f5061a07e9e5a7","status":"affected","versionType":"git"},{"version":"c2c9af9a0b13261c36909036057a116f2edb5e1a","lessThan":"4f45f276d5b4412eade6f74f2e37f3adba0473ed","status":"affected","versionType":"git"},{"version":"c2c9af9a0b13261c36909036057a116f2edb5e1a","lessThan":"bea4fe98204b6ce7eb8e29f7bf867dd7619b3ddd","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/fuse/dev_uring.c"],"versions":[{"version":"6.14","status":"affected"},{"version":"0","lessThan":"6.14","status":"unaffected","versionType":"semver"},{"version":"6.18.39","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.1.4","lessThanOrEqual":"7.1.*","status":"unaffected","versionType":"semver"},{"version":"7.2","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.14","versionEndExcluding":"6.18.39"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.14","versionEndExcluding":"7.1.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.14","versionEndExcluding":"7.2"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/bb476ef8e1027a9d509fbaaf81f5061a07e9e5a7"},{"url":"https://git.kernel.org/stable/c/4f45f276d5b4412eade6f74f2e37f3adba0473ed"},{"url":"https://git.kernel.org/stable/c/bea4fe98204b6ce7eb8e29f7bf867dd7619b3ddd"}],"title":"fuse-uring: end fuse_req on io-uring cancel task work","x_generator":{"engine":"bippy-1.2.0"}}}}