CVE-2026-45847 net: remove WARN_ON_ONCE when accessing forward path array
A reachable WARN_ON_ONCE in the Linux kernel networking stack can be triggered by crafted IPIP tunnel packets, potentially causing a 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-2026-45847?
CVE-2026-45847 is a medium-severity denial of service vulnerability in Linux kernel, published on 27 May 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:
net: remove WARN_ON_ONCE when accessing forward path array
Although unlikely, recent support for IPIP tunnels increases chances of reaching this WARN_ON_ONCE if userspace manages to build a sufficiently long forward path.
Remove it.
Weakness: CWE-617
Which versions are affected by CVE-2026-45847?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-45847?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-45847 being exploited?
There is no known exploitation of CVE-2026-45847 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-45847, DEBIAN-CVE-2026-45847, GHSA-3538-rrcv-8mrq, ROOT-OS-UBUNTU-2204-CVE-2026-45847, ROOT-OS-UBUNTU-2404-CVE-2026-45847, UBUNTU-CVE-2026-45847.