CVE-2026-90392 bpf: Fix potential UAF when reading bpf link info
A use-after-free vulnerability in the Linux kernel's BPF subsystem allows attackers to potentially execute arbitrary code or escalate privileges via concurrent link updates.
- 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-2026-90392?
CVE-2026-90392 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 potential UAF when reading bpf link info
In bpf_link_show_fdinfo and bpf_link_get_info_by_fd, link->prog is accessed without holding any locks. If the prog is concurrently replaced via bpf_link_update, the old prog can be freed, leading to a potential UAF issue.
Fix this by accessing link->prog under RCU protection to safely fetch the pointer and guarantee its lifetime while reading its fields.
Which versions are affected by CVE-2026-90392?
How do I fix CVE-2026-90392?
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-2026-90392 being exploited?
There is no known exploitation of CVE-2026-90392 in the wild and no public exploit code.
Sources
Also known as AZL-101858, BELL-CVE-2026-90392, DEBIAN-CVE-2026-90392, GHSA-crrx-xc5g-xqgw, UBUNTU-CVE-2026-90392.