io_uring/net: inherit IORING_CQE_F_BUF_MORE across bundle recv retries_CVE-2026-53191

{
    "lastseen": "",
    "description": "In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/net: inherit IORING_CQE_F_BUF_MORE across bundle recv retries\n\nWhen a bundle recv retries inside io_recv_finish(), the merge logic OR\nthe saved cflags from the previous iteration with the cflags returned by\nthe new iteration:\n  cflags = req->cqe.flags | (cflags & CQE_F_MASK);\n\nBits listed in CQE_F_MASK are inherited from the new iteration, and all\nother bits (notably IORING_CQE_F_BUFFER and the buffer ID) come from the\nsaved cflags. Before this change CQE_F_MASK covered only\nIORING_CQE_F_SOCK_NONEMPTY and IORING_CQE_F_MORE.\n\nWhen using provided buffer rings (IOU_PBUF_RING_INC) with incremental\nmode, and bundle recv, io_kbuf_inc_commit() can leave the head ring\nentry partially consumed, __io_put_kbufs() then sets\nIORING_CQE_F_BUF_MORE on the returned cflags so userspace knows the\nbuffer ID will be reused for subsequent completions.\n\nBecause IORING_CQE_F_BUF_MORE was not in CQE_F_MASK, the merge above\nsilently dropped it whenever the final retry iteration partially\nconsumed the buffer, and the subsequent req->cqe.flags = cflags &\n~CQE_F_MASK save would have left a stale IORING_CQE_F_BUF_MORE in the\ncarried-over cflags had one been present. Userspace would then\nwrongfully advance it ring head past an entry the kernel still uses.\n\nAdd IORING_CQE_F_BUF_MORE to CQE_F_MASK so it is both inherited from the\nnew iteration into the user-visible CQE and stripped from the saved\ncflags between iterations.",
    "published": "2026-06-25T08:39:03.052Z",
    "modified": "2026-06-28T06:40:06.846Z",
    "type": "cve",
    "title": "io_uring/net: inherit IORING_CQE_F_BUF_MORE across bundle recv retries",
    "source": "Linux",
    "references": "https://git.kernel.org/stable/c/f40570fda3f3a1f96aeaa4aef665ba274b2810b5\nhttps://git.kernel.org/stable/c/0bbc9481f970b0b4ddb08cfa464db1cc93b74b56\nhttps://git.kernel.org/stable/c/4973232a67e4137ab9399f504f7f2bdd847f96d2\nhttps://git.kernel.org/stable/c/ed46f39c47eb5530a9c161481a2080d3a869cfaf",
    "id": "CVE-2026-53191",
    "bulletinFamily": "",
    "cwe": null,
    "cvelist": null,
    "sourceData": "Linux Linux ae98dbf43d755b4e111fcd086e53939bef3e9a1a\nLinux Linux ae98dbf43d755b4e111fcd086e53939bef3e9a1a\nLinux Linux ae98dbf43d755b4e111fcd086e53939bef3e9a1a\nLinux Linux ae98dbf43d755b4e111fcd086e53939bef3e9a1a\nLinux Linux 6.12",
    "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": {
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        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
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            "privilegesRequired": "",
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    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Linux",
    "version": "ae98dbf43d755b4e111fcd086e53939bef3e9a1a",
    "vendor": "Linux",
    "ai_description": "",
    "ai_severity": "",
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    "ai_score": 0
}