CVE-2026-63986 ethtool: tsinfo: don't pass ERR_PTR to genlmsg_cancel on prepare failure
A local attacker can cause a kernel crash by triggering a specific error path in the ethtool timestamping interface, leading to denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-63986?
CVE-2026-63986 is a medium-severity vulnerability in Linux kernel, published on 19 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
ethtool: tsinfo: don't pass ERR_PTR to genlmsg_cancel on prepare failure
The goto err label leads to:
genlmsg_cancel(skb, ehdr); return ret;
If ethnl_tsinfo_prepare_dump() failed, it has not started a genlmsg. There's nothing to cancel, and passing an error pointer to genlmsg_cancel() would cause a crash.
Weakness: CWE-763
Which versions are affected by CVE-2026-63986?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-63986?
Apply the vendor's patch.
Is CVE-2026-63986 being exploited?
There is no known exploitation of CVE-2026-63986 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-63986, DEBIAN-CVE-2026-63986, GHSA-rj76-wchj-2f64, UBUNTU-CVE-2026-63986.