CVE-2025-40248

High

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/[email protected]/ [2]: https://lore.kernel.org/netdev/[email protected]/ [3]: https://lore.kernel.org/netdev/[email protected]/

Package Linux Kernel
Published 2025-12-04
Last modified 2026-07-30
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

7.8

out of 10
High
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected versions

Linux kernel versions 3.9 and later are affected. Fixed in 5.4.302, 5.10.247, 5.15.197, 6.1.159, 6.6.118, 6.12.60, 6.17.10, 6.18 and their respective stable series.

Affected from
≥ 3.9
Fixed in
✓ 5.4.302 5.4.x ✓ 5.10.247 5.10.x ✓ 5.15.197 5.15.x ✓ 6.1.159 6.1.x ✓ 6.6.118 6.6.x ✓ 6.12.60 6.12.x ✓ 6.17.10 6.17.x ✓ 6.18

References

9 total
Showing 5 of 9 references View all on NVD

Frequently asked questions

  • What is CVE-2025-40248?

    CVE-2025-40248 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10 . It affects Linux kernel versions from 3.9 onward and has been patched in 5.4.302, 5.10.247, 5.15.197 and others. CVE-2025-40248 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2025-40248?

    CVE-2025-40248 has a CVSS score of 7.8 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H .

  • Is there a patch available for CVE-2025-40248?

    Yes. CVE-2025-40248 has been patched. Fixed versions include 5.4.302, 5.10.247, 5.15.197 and others. If you are running Linux kernel 3.9 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2025-40248 actively exploited?

    No. CVE-2025-40248 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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