CVE-2026-53191

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.

• https://git.kernel.org/stable/c/0bbc9481f970b0b4ddb08cfa464db1cc93b74b56Patch
• https://git.kernel.org/stable/c/4973232a67e4137ab9399f504f7f2bdd847f96d2Patch
• https://git.kernel.org/stable/c/ed46f39c47eb5530a9c161481a2080d3a869cfafPatch
• https://git.kernel.org/stable/c/f40570fda3f3a1f96aeaa4aef665ba274b2810b5Patch

Published

Jun 25, 2026

Last Modified

Jul 6, 2026

Status

Analyzed

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
• AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.

• CVE-2026-53186In the Linux kernel, the following vulnerability has been re…9.1
• CVE-2026-53187In the Linux kernel, the following vulnerability has been re…7.1
• CVE-2026-53188In the Linux kernel, the following vulnerability has been re…8.8
• CVE-2026-53189In the Linux kernel, the following vulnerability has been re…7.8
• CVE-2026-5319A security vulnerability has been detected in itsourcecode P…4.3
• CVE-2026-53190In the Linux kernel, the following vulnerability has been re…5.5
• CVE-2026-53192In the Linux kernel, the following vulnerability has been re…7.8
• CVE-2026-53193In the Linux kernel, the following vulnerability has been re…7.8
• CVE-2026-53194In the Linux kernel, the following vulnerability has been re…7.8
• CVE-2026-53195In the Linux kernel, the following vulnerability has been re…7.8
• CVE-2026-53196In the Linux kernel, the following vulnerability has been re…6.8
• CVE-2026-53197In the Linux kernel, the following vulnerability has been re…5.5