CVE-2023-53491 start_kernel: Add __no_stack_protector function attribute
A missing stack protector attribute in the Linux kernel can cause a panic during early boot, leading to a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-53491?
CVE-2023-53491 is a high-severity denial of service vulnerability in Linux kernel, published on 1 Oct 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
start_kernel: Add __no_stack_protector function attribute
Back during the discussion of commit a9a3ed1eff36 ("x86: Fix early boot crash on gcc-10, third try") we discussed the need for a function attribute to control the omission of stack protectors on a per-function basis; at the time Clang had support for no_stack_protector but GCC did not. This was fixed in gcc-11. Now that the function attribute is available, let's start using it.
Callers of boot_init_stack_canary need to use this function attribute unless they're compiled with -fno-stack-protector, otherwise the canary stored in the stack slot of the caller will differ upon the call to boot_init_stack_canary. This will lead to a call to __stack_chk_fail() then panic.
Which versions are affected by CVE-2023-53491?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2023-53491?
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-2023-53491 being exploited?
There is no known exploitation of CVE-2023-53491 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-75104, BELL-CVE-2023-53491, DEBIAN-CVE-2023-53491, GHSA-w4g3-pp54-phhq, ROOT-OS-DEBIAN-11-CVE-2023-53491, ROOT-OS-DEBIAN-12-CVE-2023-53491 and 2 more.