Bug 2414492 (CVE-2025-40173) - CVE-2025-40173 kernel: net/ip6_tunnel: Prevent perpetual tunnel growth
Summary: CVE-2025-40173 kernel: net/ip6_tunnel: Prevent perpetual tunnel growth
Keywords:
Status: NEW
Alias: CVE-2025-40173
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2025-11-12 11:03 UTC by OSIDB Bzimport
Modified: 2025-11-13 15:01 UTC (History)
0 users

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


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Description OSIDB Bzimport 2025-11-12 11:03:19 UTC
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.


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