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CVE-2026-53181— vsock/vmci: fix sk_ack_backlog leak on failed handshake

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存在安全漏洞，该漏洞源于vsock/vmci在处理失败握手时未调用sk_acceptq_removed()，导致sk_ack_backlog永久递增，可能因重复握手失败（畸形分组、队列对分配失败、事件订阅失败）使监听器拒绝所有新连接，造成拒绝服务。

AI Predicted 5.3 Difficulty: Moderate EPSS 0.12% · P2

Possible ATT&CK Techniques 1 AI

T1499 · Endpoint Denial of Service

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux d021c344051af91f42c5ba9fdedc176740cbd238< 22c587aa3ab1ab5264daff3ec32136fd30436c13 affected
d021c344051af91f42c5ba9fdedc176740cbd238< cf7090e255d74c4b61c51f8ede9fcacdd8393b5b affected
d021c344051af91f42c5ba9fdedc176740cbd238< ea0b03d52881c12a8c634ea0d6cbfa61cefdb488 affected
d021c344051af91f42c5ba9fdedc176740cbd238< dfd853197615d322d3a88dbcab91fc0fd2096219 affected
d021c344051af91f42c5ba9fdedc176740cbd238< bcb275626055df7f8f947f1a349754b4004d9a15 affected
d021c344051af91f42c5ba9fdedc176740cbd238< ba9ad6015937a5e46ba1a31370e3efdec8abbdcc affected
d021c344051af91f42c5ba9fdedc176740cbd238< 9698582a4dd9c4a05889d7db96d4c0edc9e69cac affected
d021c344051af91f42c5ba9fdedc176740cbd238< c05fa14db43ebef3bd862ca9d073981c0358b3f0 affected
… +10 more rows
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I. Basic Information for CVE-2026-53181

Vulnerability Information
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Vulnerability Title
vsock/vmci: fix sk_ack_backlog leak on failed handshake
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: vsock/vmci: fix sk_ack_backlog leak on failed handshake When vmci_transport_recv_connecting_server() returns an error, vmci_transport_recv_listen() calls vsock_remove_pending() but never calls sk_acceptq_removed(). This leaves sk_ack_backlog incremented permanently. Repeated handshake failures (malformed packets, queue pair alloc failure, event subscribe failure) cause sk_ack_backlog to climb toward sk_max_ack_backlog. Once it reaches the limit the listener permanently refuses all new connections with -ECONNREFUSED, a silent denial of service requiring a process restart to recover. The two existing sk_acceptq_removed() calls in af_vsock.c do not cover this path: line 764 checks vsock_is_pending() which returns false after vsock_remove_pending(), and line 1889 is only reached on successful accept(). Fix by balancing sk_acceptq_added() with sk_acceptq_removed() on the error path.
Source: CVE Program / CVE List V5
CVSS Information
N/A
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存在安全漏洞，该漏洞源于vsock/vmci在处理失败握手时未调用sk_acceptq_removed()，导致sk_ack_backlog永久递增，可能因重复握手失败（畸形分组、队列对分配失败、事件订阅失败）使监听器拒绝所有新连接，造成拒绝服务。
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 d021c344051af91f42c5ba9fdedc176740cbd238 ~ 22c587aa3ab1ab5264daff3ec32136fd30436c13 -
Linux Linux 3.9 -

II. Public POCs for CVE-2026-53181

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III. Intelligence Information for CVE-2026-53181

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Patches & Fixes for CVE-2026-53181 (8)

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

CVE-2026-53247 9.8 CRITICAL net: ethernet: mtk_eth_soc: Fix use-after-free in metadata dst teardown
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-2026-53246 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-2026-53221 9.8 CRITICAL ip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup()
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-2026-53228 9.8 CRITICAL ipv6: sit: reload inner IPv6 header after GSO offloads
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-2026-53224 9.1 CRITICAL sctp: validate embedded INIT chunk and address list lengths in cookie
CVE-2026-53186 9.1 CRITICAL RDMA/srp: bound SRP_RSP sense copy by the received length
CVE-2026-53240 8.8 HIGH xfrm: iptfs: fix use-after-free on first_skb in __input_process_payload
CVE-2026-53232 8.8 HIGH net: phy: clean the sfp upstream if phy probing fails
CVE-2026-53248 8.8 HIGH net: airoha: Fix use-after-free in metadata dst teardown
CVE-2026-53200 8.8 HIGH KVM: arm64: nv: Fix handling of XN[0] when !FEAT_XNX
CVE-2026-53198 8.8 HIGH ksmbd: fix use-after-free of a deferred file_lock on double SMB2_CANCEL
CVE-2026-53171 8.8 HIGH accel/ethosu: fix arithmetic issues in dma_length()

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

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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