{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-46274","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-05-13T15:03:33.109Z","datePublished":"2026-06-08T14:30:53.323Z","dateUpdated":"2026-08-05T12:30:57.842Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T12:30:57.842Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nio-wq: check that the predecessor is hashed in io_wq_remove_pending()\n\nio_wq_remove_pending() needs to fix up wq->hash_tail[] if the cancelled\nwork was the tail of its hash bucket. When doing this, it checks whether\nthe preceding entry in acct->work_list has the same hash value, but\nnever checks that the predecessor is hashed at all. io_get_work_hash()\nis simply atomic_read(&work->flags) >> IO_WQ_HASH_SHIFT, and the hash\nbits are never set for non-hashed work, so it returns 0. Thus, when a\nhashed bucket-0 work is cancelled while a non-hashed work is its list\npredecessor, the check spuriously passes and a pointer to the non-hashed\nio_kiocb is stored in wq->hash_tail[0].\n\nBecause non-hashed work is dequeued via the fast path in\nio_get_next_work(), which never touches hash_tail[], the stale pointer\nis never cleared. Therefore, after the non-hashed io_kiocb completes and\nis freed back to req_cachep, wq->hash_tail[0] is a dangling pointer. The\nio_wq is per-task (tctx->io_wq) and survives ring open/close, so the\ndangling pointer persists for the lifetime of the task; the next hashed\nbucket-0 enqueue dereferences it in io_wq_insert_work() and\nwq_list_add_after() writes through freed memory.\n\nAdd the missing io_wq_is_hashed() check so a non-hashed predecessor\nnever inherits a hash_tail[] slot."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The bug is reached only through io_uring syscalls (io_uring_setup/io_uring_enter) that enqueue and cancel async io-wq work; there is no network, adjacent-radio, or physical-device entry path to io_wq_remove_pending().\nAC:L - An attacker fully controls the trigger sequence—queue a non-hashed async request, queue a hashed bucket-0 request behind it, cancel the hashed pending work, let the non-hashed work complete, then enqueue another hashed bucket-0 request—with no dependence on uncontrollable timing or rare kernel configuration.\nPR:L - Any unprivileged local user who can invoke io_uring (default when kernel.io_uring_disabled=0) can drive the cancel/enqueue sequence; no real-root or special capability beyond normal local process access is required.\nUI:N - Exploitation requires only the attacker's own io_uring submissions and cancellations; no victim user action such as opening files or mounting filesystems is needed beyond what the attacker initiates.\nS:U - The flaw corrupts kernel heap memory within the same kernel security domain to escalate from local user to kernel privileges; it does not inherently cross a VM/host or IOMMU boundary on its own.\nC:H - The stale hash_tail pointer is a use-after-free of a freed io_kiocb slab object; subsequent dereferences in io_wq_insert_work() read freed memory and UAF heap corruption is routinely weaponizable for arbitrary kernel memory disclosure.\nI:H - io_wq_insert_work() calls wq_list_add_after(), which writes attacker-influenced list pointers through the freed io_kiocb's list.next field, providing a controlled heap write primitive suitable for further memory corruption or code execution.\nA:H - Dereferencing and writing through the dangling hash_tail pointer can cause kernel oops/panic from invalid slab access, and successful heap corruption can crash or hang the system even before full exploitation."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["io_uring/io-wq.c"],"versions":[{"version":"204361a77f4018627addd4a06877448f088ddfc0","lessThan":"d6bda9df0c0a3080804181464d5c0f4d78a4e769","status":"affected","versionType":"git"},{"version":"204361a77f4018627addd4a06877448f088ddfc0","lessThan":"5a20ebf0c81b61f5ea3b1b529c100cad69b9f603","status":"affected","versionType":"git"},{"version":"204361a77f4018627addd4a06877448f088ddfc0","lessThan":"252c5051dba9c709b6a72f2866f93e5e618b3f06","status":"affected","versionType":"git"},{"version":"204361a77f4018627addd4a06877448f088ddfc0","lessThan":"d376c131af7c7739a87ff037ed2fdb67c2542c8a","status":"affected","versionType":"git"},{"version":"204361a77f4018627addd4a06877448f088ddfc0","lessThan":"d6a2d7b04b5a093021a7a0e2e69e9d5237dfa8cc","status":"affected","versionType":"git"},{"version":"13f35a2c0fd5c6a4fcd8903542b053bcc914fcf5","status":"affected","versionType":"git"},{"version":"5.8.6","lessThan":"5.9","status":"affected","versionType":"semver"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["io_uring/io-wq.c"],"versions":[{"version":"5.9","status":"affected"},{"version":"0","lessThan":"5.9","status":"unaffected","versionType":"semver"},{"version":"6.6.141","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.91","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.33","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.0.10","lessThanOrEqual":"7.0.*","status":"unaffected","versionType":"semver"},{"version":"7.1","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":"5.9","versionEndExcluding":"6.6.141"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.9","versionEndExcluding":"6.12.91"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.9","versionEndExcluding":"6.18.33"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.9","versionEndExcluding":"7.0.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.9","versionEndExcluding":"7.1"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.8.6"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/d6bda9df0c0a3080804181464d5c0f4d78a4e769"},{"url":"https://git.kernel.org/stable/c/5a20ebf0c81b61f5ea3b1b529c100cad69b9f603"},{"url":"https://git.kernel.org/stable/c/252c5051dba9c709b6a72f2866f93e5e618b3f06"},{"url":"https://git.kernel.org/stable/c/d376c131af7c7739a87ff037ed2fdb67c2542c8a"},{"url":"https://git.kernel.org/stable/c/d6a2d7b04b5a093021a7a0e2e69e9d5237dfa8cc"}],"title":"io-wq: check that the predecessor is hashed in io_wq_remove_pending()","x_generator":{"engine":"bippy-1.2.0"}}}}