CVE-2021-46908 bpf: Use correct permission flag for mixed signed bounds arithmetic
An attacker can bypass Spectre v1 masking mitigations in the Linux kernel BPF subsystem by exploiting incorrect permission flags during mixed signed bounds arithmetic.
- 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-2021-46908?
CVE-2021-46908 is a high-severity vulnerability in Linux kernel, published on 27 Feb 2024. 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: Use correct permission flag for mixed signed bounds arithmetic
We forbid adding unknown scalars with mixed signed bounds due to the spectre v1 masking mitigation. Hence this also needs bypass_spec_v1 flag instead of allow_ptr_leaks.
Which versions are affected by CVE-2021-46908?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2021-46908?
Apply the vendor's patch.
Is CVE-2021-46908 being exploited?
There is no known exploitation of CVE-2021-46908 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2021-46908, GHSA-j362-864m-wqpq, UBUNTU-CVE-2021-46908.