io-wq: check that the predecessor is hashed in io_wq_remove_pending()_CVE-2026-46274

{
    "lastseen": "",
    "description": "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.",
    "published": "2026-06-08T14:30:53.323Z",
    "modified": "2026-06-14T04:29:55.098Z",
    "type": "cve",
    "title": "io-wq: check that the predecessor is hashed in io_wq_remove_pending()",
    "source": "Linux",
    "references": "https://git.kernel.org/stable/c/d6bda9df0c0a3080804181464d5c0f4d78a4e769\nhttps://git.kernel.org/stable/c/5a20ebf0c81b61f5ea3b1b529c100cad69b9f603\nhttps://git.kernel.org/stable/c/252c5051dba9c709b6a72f2866f93e5e618b3f06\nhttps://git.kernel.org/stable/c/d376c131af7c7739a87ff037ed2fdb67c2542c8a\nhttps://git.kernel.org/stable/c/d6a2d7b04b5a093021a7a0e2e69e9d5237dfa8cc",
    "id": "CVE-2026-46274",
    "bulletinFamily": "",
    "cwe": null,
    "cvelist": null,
    "sourceData": "Linux Linux 204361a77f4018627addd4a06877448f088ddfc0\nLinux Linux 204361a77f4018627addd4a06877448f088ddfc0\nLinux Linux 204361a77f4018627addd4a06877448f088ddfc0\nLinux Linux 204361a77f4018627addd4a06877448f088ddfc0\nLinux Linux 204361a77f4018627addd4a06877448f088ddfc0\nLinux Linux 13f35a2c0fd5c6a4fcd8903542b053bcc914fcf5\nLinux Linux 5.8.6\nLinux Linux 5.9",
    "sourceHref": "",
    "cvss": {
        "score": 7.8,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Linux",
    "version": "204361a77f4018627addd4a06877448f088ddfc0",
    "vendor": "Linux",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}