CVE-2026-98603 ovpn: replace bind when clearing stale local source
A race condition in the Linux kernel OVPN module allows concurrent access to torn IPv6 addresses, potentially causing crashes or information leaks.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-98603?
CVE-2026-98603 is a vulnerability in Linux, published on 18 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
ovpn: replace bind when clearing stale local source
The UDP output fallback clears bind->local in place when the remembered source address is no longer usable. The bind is RCU-published and read locklessly by concurrent TX, so an IPv6 reader can observe a torn address.
Retry the route lookup with source address autoselection without modifying the bind. After a successful lookup, revalidate the bind and route key under peer->lock, reset the dst cache, and best-effort publish a replacement bind with a wildcard local address.
Do not cache the resolved dst when clearing the local source. Replacing the source invalidates all per-CPU cache entries, while dst_cache_set_ip4 and dst_cache_set_ip6 update only the current CPU slot. The current packet can still use the resolved route; if bind allocation fails, a later cache miss retries the repair.
Which versions are affected by CVE-2026-98603?
How do I fix CVE-2026-98603?
Apply the vendor's patch.
Is CVE-2026-98603 being exploited?
There is no known exploitation of CVE-2026-98603 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-98603, DEBIAN-CVE-2026-98603, GHSA-fvvm-56rx-vqjg, UBUNTU-CVE-2026-98603.