CVE-2026-45838 bpf: fix end-of-list detection in cgroup_storage_get_next_key()
A flaw in the Linux kernel BPF subsystem allows attackers to read sensitive kernel memory via a null pointer dereference in cgroup storage key retrieval.
- 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-2026-45838?
CVE-2026-45838 is a medium-severity 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:
bpf: fix end-of-list detection in cgroup_storage_get_next_key()
list_next_entry() never returns NULL -- when the current element is the last entry it wraps to the list head via container_of(). The subsequent NULL check is therefore dead code and get_next_key() never returns -ENOENT for the last element, instead reading storage->key from a bogus pointer that aliases internal map fields and copying the result to userspace.
Replace it with list_entry_is_head() so the function correctly returns -ENOENT when there are no more entries.
Weakness: CWE-476
Which versions are affected by CVE-2026-45838?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-45838?
Apply the vendor's patch.
Is CVE-2026-45838 being exploited?
There is no known exploitation of CVE-2026-45838 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-88662, BELL-CVE-2026-45838, DEBIAN-CVE-2026-45838, GHSA-x78h-gf69-p5j6, ROOT-OS-DEBIAN-11-CVE-2026-45838, ROOT-OS-DEBIAN-12-CVE-2026-45838 and 4 more.