CVE-2026-53191 (GCVE-0-2026-53191)

Vulnerability from cvelistv5 – Published: 2026-06-25 08:39 – Updated: 2026-08-05 12:33
VLAI
Title
io_uring/net: inherit IORING_CQE_F_BUF_MORE across bundle recv retries
Summary
In the Linux kernel, the following vulnerability has been resolved: io_uring/net: inherit IORING_CQE_F_BUF_MORE across bundle recv retries When a bundle recv retries inside io_recv_finish(), the merge logic OR the saved cflags from the previous iteration with the cflags returned by the new iteration: cflags = req->cqe.flags | (cflags & CQE_F_MASK); Bits listed in CQE_F_MASK are inherited from the new iteration, and all other bits (notably IORING_CQE_F_BUFFER and the buffer ID) come from the saved cflags. Before this change CQE_F_MASK covered only IORING_CQE_F_SOCK_NONEMPTY and IORING_CQE_F_MORE. When using provided buffer rings (IOU_PBUF_RING_INC) with incremental mode, and bundle recv, io_kbuf_inc_commit() can leave the head ring entry partially consumed, __io_put_kbufs() then sets IORING_CQE_F_BUF_MORE on the returned cflags so userspace knows the buffer ID will be reused for subsequent completions. Because IORING_CQE_F_BUF_MORE was not in CQE_F_MASK, the merge above silently dropped it whenever the final retry iteration partially consumed the buffer, and the subsequent req->cqe.flags = cflags & ~CQE_F_MASK save would have left a stale IORING_CQE_F_BUF_MORE in the carried-over cflags had one been present. Userspace would then wrongfully advance it ring head past an entry the kernel still uses. Add IORING_CQE_F_BUF_MORE to CQE_F_MASK so it is both inherited from the new iteration into the user-visible CQE and stripped from the saved cflags between iterations.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: ae98dbf43d755b4e111fcd086e53939bef3e9a1a , < f40570fda3f3a1f96aeaa4aef665ba274b2810b5 (git)
Affected: ae98dbf43d755b4e111fcd086e53939bef3e9a1a , < 0bbc9481f970b0b4ddb08cfa464db1cc93b74b56 (git)
Affected: ae98dbf43d755b4e111fcd086e53939bef3e9a1a , < 4973232a67e4137ab9399f504f7f2bdd847f96d2 (git)
Affected: ae98dbf43d755b4e111fcd086e53939bef3e9a1a , < ed46f39c47eb5530a9c161481a2080d3a869cfaf (git)
guessed Create a notification for this product.
Linux Linux Affected: 6.12
Unaffected: 0 , < 6.12 (semver)
Unaffected: 6.12.94 , ≤ 6.12.* (semver)
Unaffected: 6.18.36 , ≤ 6.18.* (semver)
Unaffected: 7.0.13 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
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      "cve": "CVE-2026-53191",
      "id": "CVE-2026-53191",
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      "product_status:known_affected": "184",
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      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: io_uring/net: inherit IORING_CQE_F_BUF_MORE across bundle recv retries",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53191.json",
      "version": "3"
    },
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      "current_release_date": "2026-09-10T02:39:21Z",
      "cve": "CVE-2026-53191",
      "id": "CVE-2026-53191",
      "initial_release_date": "2026-06-26T02:10:37Z",
      "product_status:first_fixed": "2",
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      "product_status:recommended": "145",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-53191",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-53191.json",
      "version": "14"
    }
  }
}



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