{ "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" } } } }