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CVE-2026-53191— io_uring/net: inherit IORING_CQE_F_BUF_MORE across bundle recv retries

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会开源的操作系统Linux所使用的内核。 Linux kernel 6.12版本存在安全漏洞，该漏洞源于在io_uring/net中的bundle recv重试时，合并逻辑未包含IORING_CQE_F_BUF_MORE标志于CQE_F_MASK中，导致该标志被静默丢弃，用户空间可能错误地推进ring head到内核仍在使用的条目。

CVSS 7.8 · High EPSS 0.13% · P2

Affected Version Matrix 10

VendorProduct Version RangeStatus
Linux Linux ae98dbf43d755b4e111fcd086e53939bef3e9a1a< f40570fda3f3a1f96aeaa4aef665ba274b2810b5 affected
ae98dbf43d755b4e111fcd086e53939bef3e9a1a< 0bbc9481f970b0b4ddb08cfa464db1cc93b74b56 affected
ae98dbf43d755b4e111fcd086e53939bef3e9a1a< 4973232a67e4137ab9399f504f7f2bdd847f96d2 affected
ae98dbf43d755b4e111fcd086e53939bef3e9a1a< ed46f39c47eb5530a9c161481a2080d3a869cfaf affected
6.12 affected
< 6.12 unaffected
6.12.94≤ 6.12.* unaffected
6.18.36≤ 6.18.* unaffected
… +2 more rows
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I. Basic Information for CVE-2026-53191

Vulnerability Information
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Vulnerability Title
io_uring/net: inherit IORING_CQE_F_BUF_MORE across bundle recv retries
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会开源的操作系统Linux所使用的内核。 Linux kernel 6.12版本存在安全漏洞，该漏洞源于在io_uring/net中的bundle recv重试时，合并逻辑未包含IORING_CQE_F_BUF_MORE标志于CQE_F_MASK中，导致该标志被静默丢弃，用户空间可能错误地推进ring head到内核仍在使用的条目。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux ae98dbf43d755b4e111fcd086e53939bef3e9a1a ~ f40570fda3f3a1f96aeaa4aef665ba274b2810b5 -
Linux Linux 6.12 -

II. Public POCs for CVE-2026-53191

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III. Intelligence Information for CVE-2026-53191

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Patches & Fixes for CVE-2026-53191 (4)

Same Patch Batch · Linux · 2026-06-25 · 146 CVEs total

CVE-2026-53228 9.8 CRITICAL ipv6: sit: reload inner IPv6 header after GSO offloads
CVE-2026-53247 9.8 CRITICAL net: ethernet: mtk_eth_soc: Fix use-after-free in metadata dst teardown
CVE-2026-53246 9.8 CRITICAL sctp: validate cached peer INIT chunk length in COOKIE_ECHO processing
CVE-2026-53151 9.8 CRITICAL rxrpc: Fix the ACK parser to extract the SACK table for parsing
CVE-2026-53260 9.8 CRITICAL tcp: Add preempt_{disable,enable}_nested() in reqsk_queue_hash_req().
CVE-2026-53175 9.8 CRITICAL inet: frags: fix use-after-free caused by the fqdir_pre_exit() flush
CVE-2026-53176 9.8 CRITICAL IB/isert: Reject login PDUs shorter than ISER_HEADERS_LEN
CVE-2026-53221 9.8 CRITICAL ip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup()
CVE-2026-53215 9.8 CRITICAL net: mvpp2: refill RX buffers before XDP or skb use
CVE-2026-53216 9.8 CRITICAL net: mvpp2: limit XDP frame size to the RX buffer
CVE-2026-53131 9.4 CRITICAL netfilter: require Ethernet MAC header before using eth_hdr()
CVE-2026-53225 9.1 CRITICAL sctp: fix uninit-value in __sctp_rcv_asconf_lookup()
CVE-2026-53186 9.1 CRITICAL RDMA/srp: bound SRP_RSP sense copy by the received length
CVE-2026-53224 9.1 CRITICAL sctp: validate embedded INIT chunk and address list lengths in cookie
CVE-2026-53200 8.8 HIGH KVM: arm64: nv: Fix handling of XN[0] when !FEAT_XNX
CVE-2026-53248 8.8 HIGH net: airoha: Fix use-after-free in metadata dst teardown
CVE-2026-53159 8.8 HIGH misc: fastrpc: fix DMA address corruption due to find_vma misuse
CVE-2026-53198 8.8 HIGH ksmbd: fix use-after-free of a deferred file_lock on double SMB2_CANCEL
CVE-2026-53188 8.8 HIGH RDMA/core: Validate the passed in fops for ib_get_ucaps()
CVE-2026-53232 8.8 HIGH net: phy: clean the sfp upstream if phy probing fails

Showing top 20 of 146 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-53191

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