CVE-2025-39718

Medium

In the Linux kernel, the following vulnerability has been resolved: vsock/virtio: Validate length in packet header before skb_put() When receiving a vsock packet in the guest, only the virtqueue buffer size is validated prior to virtio_vsock_skb_rx_put(). Unfortunately, virtio_vsock_skb_rx_put() uses the length from the packet header as the length argument to skb_put(), potentially resulting in SKB overflow if the host has gone wonky. Validate the length as advertised by the packet header before calling virtio_vsock_skb_rx_put().

Package Linux Kernel
Published 2025-09-05
Last modified 2026-05-12
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

5.5

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

Weakness type

CWE-787

CVE-2025-39718 is a Out-of-bounds Write vulnerability

What is Out-of-bounds Write?

The product writes data past the end or before the beginning of the intended buffer. Learn more on MITRE CWE

Affected versions

Linux kernel versions 6.1.63, 6.3 and later are affected. Fixed in 6.1.149, 6.6.103, 6.12.44, 6.16.4, 6.17 and their respective stable series.

Affected from
≥ 6.1.63 ≥ 6.3
Fixed in
✓ 6.1.149 6.1.x ✓ 6.6.103 6.6.x ✓ 6.12.44 6.12.x ✓ 6.16.4 6.16.x ✓ 6.17

References

The following references provide additional information about CVE-2025-39718 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

5 patch commits total View all on NVD

Frequently asked questions

  • What is CVE-2025-39718?

    CVE-2025-39718 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 , classified as an Out-of-bounds Write flaw (CWE-787) . It affects Linux kernel versions from 6.1.63 onward and has been patched in 6.1.149, 6.6.103, 6.12.44 and others. CVE-2025-39718 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2025-39718?

    CVE-2025-39718 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H .

  • Is there a patch available for CVE-2025-39718?

    Yes — CVE-2025-39718 has been patched. Fixed versions include 6.1.149, 6.6.103, 6.12.44 and others. If you are running Linux kernel 6.1.63 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2025-39718 actively exploited?

    No — CVE-2025-39718 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

  • What is Out-of-bounds Write (CWE-787)?

    The product writes data past the end or before the beginning of the intended buffer. View CWE-787 on MITRE CWE →

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