Linux kernel vsock: Race condition in connect() can corrupt memory
Summary
The vsock (VM Sockets) subsystem of the Linux kernel has a race condition between connect() and an OP_RST reset. A socket that is still in the connected table can be reset, which can corrupt kernel list structures and crash the system. Per the CNA record, affected kernels range from 3.9 up to the fixed stable releases. The reporter reproduced crashes, and the CVSS vector claims high impact, but the attack vector is disputed between local and remote and NVD had not finished its analysis.
Affected
- Linux kernel with the vsock subsystem, from 3.9 up to the fixed stable releases
- Per the CNA record, the 5.10, 5.15, 6.1, 6.6, 6.12 and 6.18 branches and 7.2 are affected before the fixed releases listed below
Fixed in
- 5.10.273, 5.15.224, 6.1.191, 6.6.161, 6.12.115, 6.18.59 and 7.2.13 (per CNA record and OSV)
- Distribution kernel versions: Unknown.
Workaround
- No vendor workaround documented.
- Interim option (general advice, not from a source): on hosts that do not use vsock, unload the vsock transport modules. Test first, because VM management agents may depend on them.
Exploitation
- Not known to be exploited; not listed in CISA KEV at the time of research.
- No public exploit known; the reporter reproduced crashes.
Our recommendation
- Update the Linux kernel to a fixed stable release from your distribution or kernel.org.
- Prioritise virtualization hosts and systems where untrusted local users run code.
- Check your distribution's advisory, because some distributions still list the CVE as needing evaluation and the upstream fix may be incomplete.
- Monitor kernel logs for list_add or BUG messages originating in vsock code.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Linux kernel stable commit 44d1ca05 git.kernel.org
- Linux kernel stable commit ea36ef3c git.kernel.org
- Linux kernel stable commit f89770c7 git.kernel.org
- Strix CVE analysis www.strix.ai
- VulDB entry 427940 vuldb.com
- Red Hat security data access.redhat.com
- Ubuntu security tracker ubuntu.com
- Patch review discussion (mail archive) www.mail-archive.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 1 Nov 2026, 21:56.
Original description (NVD)
In the Linux kernel, the following vulnerability has been resolved: vsock: treat TCP_CLOSING as once-established Handle the TCP_ESTABLISHED -> TCP_CLOSING transition on OP_RST, which can race with the connect loop. Immediately break and return 0 on ESTABLISHED/CLOSING. The return value of connect() should reflect what happened up to the point the connection was established or failed. Events that occur afterwards must not affect it. E.g. even if OP_RW has already set sk_err, connect() should still return 0, not ENOBUFS because of it. Adapt the inaccurate comment above signal_pending(). Resetting a socket that is still present in connected_table can lead to memory corruption. The reporter noted lost transports for in-flight skbs, and I have reproduced crashes caused by re-insertion into connected_table. list_add double add: new=, prev=, next=. kernel BUG at lib/list_debug.c:35! Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI Workqueue: vsock-loopback vsock_loopback_work RIP: 0010:__list_add_valid_or_report+0x11f/0x130 Call Trace: vsock_insert_connected.cold+0xe/0x13 virtio_transport_recv_pkt+0x10e9/0x1460 vsock_loopback_work+0x305/0x480 process_one_work+0xe4c/0x1560 worker_thread+0x4f1/0xd60 kthread+0x36e/0x470 ret_from_fork+0x47b/0x6b0 ret_from_fork_asm+0x1a/0x30 This fix is supplementary to commit 002541ef650b ("vsock: Ignore signal/timeout on connect() if already established"). Details under Link.
NVD references (8)
- https://git.kernel.org/stable/c/44d1ca05d6094a5d75c671a0545249186d790b8d
- https://git.kernel.org/stable/c/4f6ac74fa594a918d41255c941256e1d51592d3b
- https://git.kernel.org/stable/c/5f2ab77028602a22f0cc33cac063a313787cbeae
- https://git.kernel.org/stable/c/baf1b5715640e434249ce7f63f94bd1a00938ef9
- https://git.kernel.org/stable/c/c2c5359ef2c33684fa3f3652fd761a483db8d1e7
- https://git.kernel.org/stable/c/deb972c7eea8d0bc3109c35c30a1c86d4939f811
- https://git.kernel.org/stable/c/ea36ef3c229d54b552432d1290aee1d807f67fd5
- https://git.kernel.org/stable/c/f89770c7365748d9d6a2ae07d1c23497ca21ec07
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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