CVE-2025-40127 hwrng: ks-sa - fix division by zero in ks_sa_rng_init
A division by zero error in the ks-sa hardware random number generator driver can cause a kernel crash, leading to 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-2025-40127?
CVE-2025-40127 is a denial of service vulnerability in Linux, published on 12 Nov 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:
hwrng: ks-sa - fix division by zero in ks_sa_rng_init
Fix division by zero in ks_sa_rng_init caused by missing clock pointer initialization. The clk_get_rate() call is performed on an uninitialized clk pointer, resulting in division by zero when calculating delay values.
Add clock initialization code before using the clock.
drivers/char/hw_random/ks-sa-rng.c | 7 +++++++ 1 file changed, 7 insertions(+)
Which versions are affected by CVE-2025-40127?
How do I fix CVE-2025-40127?
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-2025-40127 being exploited?
There is no known exploitation of CVE-2025-40127 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2025-40127, DEBIAN-CVE-2025-40127, GHSA-666w-62rj-5fc6, ROOT-OS-DEBIAN-11-CVE-2025-40127, ROOT-OS-DEBIAN-13-CVE-2025-40127, ROOT-OS-UBUNTU-2404-CVE-2025-40127 and 1 more.