Improper input validation in Linux kernel - CVE-2026-64537

Vulnerability details

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to improper input validation in the bridge cfm ccm transmission logic when configuring an invalid ccm interval. A local user can set an invalid expiration interval to trigger a tight workqueue loop and exhaust memory to cause a denial of service.

The issue can result in immediate re-arming of delayed work and repeated skb allocations until out-of-memory conditions occur.

Affected software

How to mitigate CVE-2026-64537

External References

• https://git.kernel.org/stable/c/2870056a78961e0fecd652362ee9d3fcfd24a8a6
• https://git.kernel.org/stable/c/53788b134519e995699ea3721969c96a08d64575
• https://git.kernel.org/stable/c/865643640b5b5c4579b32d7a55ac9ad648362eaa
• https://git.kernel.org/stable/c/a090880c1f544589427e5b7050c40fb211ccecb4
• https://git.kernel.org/stable/c/b42aeb58317f12024734759ff745856b53948873
• https://git.kernel.org/stable/c/f0f5eb59a97ece0d85de8cfa95dc18c609302a8b
• https://git.kernel.org/stable/c/f3e02edd8322b31b8e6517faa6ba053bf29d1e26

Related Security Bulletins

• Improper input validation in Linux kernel bridge
• Debian update for linux