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vuln-cve/data/2026/64xxx/CVE-2026-64262.json
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{
"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"
}
}
}
}