CVE-2026-53191io_uring/net: inherit IORING_CQE_F_BUF_MORE across bundle recv retries
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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.
- CVSS
- 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Analyzed
- Record last updated
- Oct 16, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from ae98dbf43d755b4e111fcd086e53939bef3e9a1a before f40570fda3f3a1f96aeaa4aef665ba274b2810b5; from ae98dbf43d755b4e111fcd086e53939bef3e9a1a before 0bbc9481f970b0b4ddb08cfa464db1cc93b74b56; from ae98dbf43d755b4e111fcd086e53939bef3e9a1a before 4973232a67e4137ab9399f504f7f2bdd847f96d2; from ae98dbf43d755b4e111fcd086e53939bef3e9a1a before ed46f39c47eb5530a9c161481a2080d3a869cfaf | CNA record |
linux linux_kernel linux:linux_kernel | from 6.12 before 6.12.94; from 6.13 before 6.18.36; from 6.19 before 7.0.13; 7.1; 7.1; 7.1; 7.1; 7.1; and 1 more ranges | NVD |
References
- https://git.kernel.org/stable/c/f40570fda3f3a1f96aeaa4aef665ba274b2810b5patch
- https://git.kernel.org/stable/c/0bbc9481f970b0b4ddb08cfa464db1cc93b74b56patch
- https://git.kernel.org/stable/c/4973232a67e4137ab9399f504f7f2bdd847f96d2patch
- https://git.kernel.org/stable/c/ed46f39c47eb5530a9c161481a2080d3a869cfafpatch
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.