CVE-2026-90210 bpf: Fix UAF in bpf_trampoline_multi_attach_free on update failure
A use-after-free vulnerability in the Linux kernel's BPF trampoline handling allows attackers to potentially execute arbitrary code or escalate privileges.
- 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-2026-90210?
CVE-2026-90210 is a high-severity use after free vulnerability in Linux, published on 17 Sep 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: Fix UAF in bpf_trampoline_multi_attach_free on update failure
When bpf_trampoline_update() fails before modify_fentry_multi()/ unregister_fentry_multi() is called, cur_image is unchanged (cur_image == old_image) and ftrace still calls into it. Freeing old_image in that case causes a UAF.
Only free old_image when it differs from cur_image.
Which versions are affected by CVE-2026-90210?
How do I fix CVE-2026-90210?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-90210 being exploited?
There is no known exploitation of CVE-2026-90210 in the wild and no public exploit code.
Sources
Also known as GHSA-gj8p-gx9h-pwwh, UBUNTU-CVE-2026-90210.