CVE-2025-21854

Published Mar 12, 2025

Last updated a year ago

CVSS medium 5.5

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: sockmap, vsock: For connectible sockets allow only connected sockmap expects all vsocks to have a transport assigned, which is expressed in vsock_proto::psock_update_sk_prot(). However, there is an edge case where an unconnected (connectible) socket may lose its previously assigned transport. This is handled with a NULL check in the vsock/BPF recv path. Another design detail is that listening vsocks are not supposed to have any transport assigned at all. Which implies they are not supported by the sockmap. But this is complicated by the fact that a socket, before switching to TCP_LISTEN, may have had some transport assigned during a failed connect() attempt. Hence, we may end up with a listening vsock in a sockmap, which blows up quickly: KASAN: null-ptr-deref in range [0x0000000000000120-0x0000000000000127] CPU: 7 UID: 0 PID: 56 Comm: kworker/7:0 Not tainted 6.14.0-rc1+ Workqueue: vsock-loopback vsock_loopback_work RIP: 0010:vsock_read_skb+0x4b/0x90 Call Trace: sk_psock_verdict_data_ready+0xa4/0x2e0 virtio_transport_recv_pkt+0x1ca8/0x2acc vsock_loopback_work+0x27d/0x3f0 process_one_work+0x846/0x1420 worker_thread+0x5b3/0xf80 kthread+0x35a/0x700 ret_from_fork+0x2d/0x70 ret_from_fork_asm+0x1a/0x30 For connectible sockets, instead of relying solely on the state of vsk->transport, tell sockmap to only allow those representing established connections. This aligns with the behaviour for AF_INET and AF_UNIX.
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Modified
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Primary
Base score
5.5
Impact score
3.6
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Severity
MEDIUM

Weaknesses

nvd@nist.gov
CWE-476
134c704f-9b21-4f2e-91b3-4a467353bcc0
CWE-476

Social media

Hype score
Not currently trending

  1. CVE-2025-21854 In the Linux kernel, the following vulnerability has been resolved: sockmap, vsock: For connectible sockets allow only connected sockmap expects all vsocks to have … https://t.co/aKIlT8M1Sp

    @CVEnew

    12 Mar 2025

    229 Impressions

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Configurations

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References

Sources include official advisories and independent security research.