CVE-2026-43306 bpf: crypto: Use the correct destructor kfunc type
A type mismatch in BPF crypto destructor kfuncs causes a kernel crash when Control Flow Integrity is enabled, 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-2026-43306?
CVE-2026-43306 is a medium-severity vulnerability in Linux kernel, published on 8 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:
bpf: crypto: Use the correct destructor kfunc type
With CONFIG_CFI enabled, the kernel strictly enforces that indirect function calls use a function pointer type that matches the target function. I ran into the following type mismatch when running BPF self-tests:
CFI failure at bpf_obj_free_fields+0x190/0x238 (target: bpf_crypto_ctx_release+0x0/0x94; expected type: 0xa488ebfc) Internal error: Oops - CFI: 00000000f2008228 [#1] SMP ...
As bpf_crypto_ctx_release() is also used in BPF programs and using a void pointer as the argument would make the verifier unhappy, add a simple stub function with the correct type and register it as the destructor kfunc instead.
Which versions are affected by CVE-2026-43306?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-43306?
Apply the vendor's patch.
Is CVE-2026-43306 being exploited?
There is no known exploitation of CVE-2026-43306 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-86148, BELL-CVE-2026-43306, DEBIAN-CVE-2026-43306, GHSA-q637-vrq8-p3jv, ROOT-OS-DEBIAN-11-CVE-2026-43306, ROOT-OS-DEBIAN-12-CVE-2026-43306 and 3 more.