CVE-2023-54056 kheaders: Use array declaration instead of char
A local attacker can trigger a kernel panic via the kheaders interface when CONFIG_FORTIFY_SOURCE is enabled, causing a denial of service.
- 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-2023-54056?
CVE-2023-54056 is a denial of service vulnerability in Linux, published on 24 Dec 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:
kheaders: Use array declaration instead of char
Under CONFIG_FORTIFY_SOURCE, memcpy() will check the size of destination and source buffers. Defining kernel_headers_data as "char" would trip this check. Since these addresses are treated as byte arrays, define them as arrays (as done everywhere else).
This was seen with:
$ cat /sys/kernel/kheaders.tar.xz >> /dev/null
detected buffer overflow in memcpy kernel BUG at lib/string_helpers.c:1027! ... RIP: 0010:fortify_panic+0xf/0x20 [...] Call Trace: <TASK> ikheaders_read+0x45/0x50 [kheaders] kernfs_fop_read_iter+0x1a4/0x2f0 ...
Which versions are affected by CVE-2023-54056?
How do I fix CVE-2023-54056?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2023-54056 being exploited?
There is no known exploitation of CVE-2023-54056 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2023-54056, DEBIAN-CVE-2023-54056, GHSA-w8p6-7x4v-892g, UBUNTU-CVE-2023-54056.