CVE-2023-53516 macvlan: add forgotten nla_policy for IFLA_MACVLAN_BC_CUTOFF
A missing netlink policy in the Linux kernel macvlan driver allows heap out-of-bounds reads, potentially leading to code execution or privilege escalation.
- 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-2023-53516?
CVE-2023-53516 is a high-severity memory corruption vulnerability in Linux kernel, published on 1 Oct 2025. 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:
macvlan: add forgotten nla_policy for IFLA_MACVLAN_BC_CUTOFF
The previous commit 954d1fa1ac93 ("macvlan: Add netlink attribute for broadcast cutoff") added one additional attribute named IFLA_MACVLAN_BC_CUTOFF to allow broadcast cutfoff.
However, it forgot to describe the nla_policy at macvlan_policy (drivers/net/macvlan.c). Hence, this suppose NLA_S32 (4 bytes) integer can be faked as empty (0 bytes) by a malicious user, which could leads to OOB in heap just like CVE-2023-3773.
To fix it, this commit just completes the nla_policy description for IFLA_MACVLAN_BC_CUTOFF. This enforces the length check and avoids the potential OOB read.
Weakness: CWE-787
Which versions are affected by CVE-2023-53516?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2023-53516?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2023-53516 being exploited?
There is no known exploitation of CVE-2023-53516 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2023-53516, DEBIAN-CVE-2023-53516, GHSA-m235-57qr-6fh8, UBUNTU-CVE-2023-53516.