What is CVE-2025-40173?

CVE-2025-40173 is a unscored severity Linux kernel vulnerability, affecting Linux kernel versions from 4.7 onward and patched in 5.4.301, 5.10.246, 5.15.196 and others. CVE-2025-40173 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2025-40173?

CVE-2025-40173 has a CVSS score of pending NVD analysis out of 10, rated awaiting scoring severity.

Is there a patch available for CVE-2025-40173?

Yes, CVE-2025-40173 has been patched. Fixed versions include 5.4.301, 5.10.246, 5.15.196 and others. If you are running Linux kernel 4.7 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2025-40173 actively exploited?

CVE-2025-40173 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2025-40173

In the Linux kernel, the following vulnerability has been resolved: net/ip6_tunnel: Prevent perpetual tunnel growth Similarly to ipv4 tunnel, ipv6 version updates dev->needed_headroom, too. While ipv4 tunnel headroom adjustment growth was limited in commit 5ae1e9922bbd ("net: ip_tunnel: prevent perpetual headroom growth"), ipv6 tunnel yet increases the headroom without any ceiling. Reflect ipv4 tunnel headroom adjustment limit on ipv6 version. Credits to Francesco Ruggeri, who was originally debugging this issue and wrote local Arista-specific patch and a reproducer.

Package Linux Kernel

Published 2025-11-12

Last modified 2026-04-15

Patch available

Yes

Affected versions

Linux kernel versions 4.7 and later are affected. Fixed in 5.4.301, 5.10.246, 5.15.196, 6.1.158, 6.6.114, 6.12.55, 6.17.5, 6.18 and their respective stable series.

Affected from

≥ 4.7

Fixed in

✓ 5.4.301 5.4.x ✓ 5.10.246 5.10.x ✓ 5.15.196 5.15.x ✓ 6.1.158 6.1.x ✓ 6.6.114 6.6.x ✓ 6.12.55 6.12.x ✓ 6.17.5 6.17.x ✓ 6.18

References

The following references provide additional information about CVE-2025-40173 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

Kernel patch commit
https://git.kernel.org/stable/c/10fe967efe73c610e526ff7460581610633dee9c
Patch
Kernel patch commit
https://git.kernel.org/stable/c/11f6066af3bfb8149aa16c42c0b0c5ea5b199a94
Patch
Kernel patch commit
https://git.kernel.org/stable/c/21f4d45eba0b2dcae5dbc9e5e0ad08735c993f16
Patch

8 patch commits total View all on NVD

Frequently asked questions

What is CVE-2025-40173?

CVE-2025-40173 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 4.7 onward and has been patched in 5.4.301, 5.10.246, 5.15.196 and others. CVE-2025-40173 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
Is there a patch available for CVE-2025-40173?

Yes — CVE-2025-40173 has been patched. Fixed versions include 5.4.301, 5.10.246, 5.15.196 and others. If you are running Linux kernel 4.7 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2025-40173 actively exploited?

No — CVE-2025-40173 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.