CVE-2025-40248

high

Published 2026-01-26 · Modified 2026-01-30

CVSS v3

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CVSS v2

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VIR risk

8.0

Description

In the Linux kernel, the following vulnerability has been resolved: vsock: Ignore signal/timeout on connect() if already established During connect(), acting on a signal/timeout by disconnecting an already established socket leads to several issues: 1. connect() invoking vsock_transport_cancel_pkt() -> virtio_transport_purge_skbs() may race with sendmsg() invoking virtio_transport_get_credit(). This results in a permanently elevated `vvs->bytes_unsent`. Which, in turn, confuses the SOCK_LINGER handling. 2. connect() resetting a connected socket's state may race with socket being placed in a sockmap. A disconnected socket remaining in a sockmap breaks sockmap's assumptions. And gives rise to WARNs. 3. connect() transitioning SS_CONNECTED -> SS_UNCONNECTED allows for a transport change/drop after TCP_ESTABLISHED. Which poses a problem for any simultaneous sendmsg() or connect() and may result in a use-after-free/null-ptr-deref. Do not disconnect socket on signal/timeout. Keep the logic for unconnected sockets: they don't linger, can't be placed in a sockmap, are rejected by sendmsg(). [1]: https://lore.kernel.org/netdev/e07fd95c-9a38-4eea-9638-133e38c2ec9b@rbox.co/ [2]: https://lore.kernel.org/netdev/20250317-vsock-trans-signal-race-v4-0-fc8837f3f1d4@rbox.co/ [3]: https://lore.kernel.org/netdev/60f1b7db-3099-4f6a-875e-af9f6ef194f6@rbox.co/

Predictions

Exploit likelihood

20%

Patch ETA

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Heuristic predictions, AS-IS, for prioritization only.

Mitigations

vendor Authored 2026-05-27

Vendor advisory: alma — https://errata.almalinux.org/9/ALSA-2026-1143.html

vendor Authored 2026-05-27

Vendor advisory: alma — https://bugzilla.redhat.com/2422840

vendor Authored 2026-05-27

Vendor advisory: alma — https://bugzilla.redhat.com/2422836

vendor Authored 2026-05-27

Vendor advisory: alma — https://bugzilla.redhat.com/2419891

vendor Authored 2026-05-27

Vendor advisory: alma — https://bugzilla.redhat.com/2418876

vendor Authored 2026-05-27

Vendor advisory: alma — https://bugzilla.redhat.com/2393488

vendor Authored 2026-05-27

Vendor advisory: alma — https://bugzilla.redhat.com/2381870

vendor Authored 2026-05-27

Vendor advisory: alma — https://bugzilla.redhat.com/2376052

vendor Authored 2026-05-27

Vendor advisory: alma — https://errata.almalinux.org/8/ALSA-2026-1148.html

vendor Authored 2026-05-27

Vendor advisory: alma — https://access.redhat.com/errata/RHSA-2026:1148

vendor Authored 2026-05-27

Vendor advisory: alma — https://errata.almalinux.org/8/ALSA-2026-1142.html

vendor Authored 2026-05-27

Vendor advisory: alma — https://bugzilla.redhat.com/2419954

vendor Authored 2026-05-27

Vendor advisory: alma — https://bugzilla.redhat.com/2418872

vendor Authored 2026-05-27

Vendor advisory: alma — https://bugzilla.redhat.com/2414494

vendor Authored 2026-05-27

Vendor advisory: alma — https://bugzilla.redhat.com/2402193

vendor Authored 2026-05-27

Vendor advisory: alma — https://access.redhat.com/errata/RHSA-2026:1142

vendor Authored 2026-05-27

Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2025-40248

vendor Authored 2026-05-27

Vendor advisory: rocky — https://errata.rockylinux.org/RLSA-2026:1143

vendor Authored 2026-05-27

Vendor advisory: suse — https://www.suse.com/security/cve/CVE-2025-40248.html

vendor Authored 2026-05-27

Vendor advisory: redhat — https://access.redhat.com/errata/RHSA-2026:3987

vendor Authored 2026-05-27

Vendor advisory: redhat — https://access.redhat.com/errata/RHSA-2026:1143

vendor Authored 2026-05-27

Vendor advisory: rocky — https://errata.rockylinux.org/RLSA-2026:1142

vendor Authored 2026-05-27

Vendor advisory: rocky — https://errata.rockylinux.org/RLSA-2026:1148

OS impact

OS	Version	Status	Fixed in
rocky	8	fixed
rhel	9	fixed
sles		affected
rocky	9	fixed
debian	bookworm	fixed	`6.1.159-1`
debian	bullseye	fixed	`5.10.247-1`
debian	forky	fixed	`6.17.10-1`
debian	sid	fixed	`6.17.10-1`
debian	trixie	fixed	`6.12.63-1`

References

Verify integrity in audit chain (admin only). AS-IS.