CVE-2026-63926 bpf: sockmap: fix tail fragment offset in bpf_msg_push_data
An integer overflow in the Linux kernel's BPF sockmap allows attackers to corrupt memory, potentially leading to code execution or privilege escalation.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-63926?
CVE-2026-63926 is a high-severity vulnerability in Linux kernel, published on 19 Jul 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: sockmap: fix tail fragment offset in bpf_msg_push_data
When bpf_msg_push_data() inserts data in the middle of a scatterlist entry, it splits the original entry into a left fragment and a right fragment.
The right fragment offset is page-local, but the code advances it with `start`, which is the message-global insertion point. For inserts into a non-first SG entry, this over-advances the offset and leaves the split layout inconsistent.
Advance the right fragment offset by the fragment-local delta, `start - offset`, which matches the length removed from the front of the original entry.
Which versions are affected by CVE-2026-63926?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-63926?
Apply the vendor's patch.
Is CVE-2026-63926 being exploited?
There is no known exploitation of CVE-2026-63926 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-63926, DEBIAN-CVE-2026-63926, GHSA-39fm-rjr2-46w3, ROOT-OS-UBUNTU-2204-CVE-2026-63926, UBUNTU-CVE-2026-63926.