CVE-2025-37984 crypto: ecdsa - Harden against integer overflows in DIV_ROUND_UP()
An integer overflow in the Linux kernel's ECDSA crypto module can cause a denial of service when processing large key sizes.
- 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-2025-37984?
CVE-2025-37984 is a high-severity vulnerability in Linux kernel, published on 20 May 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:
crypto: ecdsa - Harden against integer overflows in DIV_ROUND_UP()
Herbert notes that DIV_ROUND_UP() may overflow unnecessarily if an ecdsa implementation's ->key_size() callback returns an unusually large value. Herbert instead suggests (for a division by 8):
X / 8 + !!(X & 7)
Based on this formula, introduce a generic DIV_ROUND_UP_POW2() macro and use it in lieu of DIV_ROUND_UP() for ->key_size() return values.
Additionally, use the macro in ecc_digits_from_bytes(), whose "nbytes" parameter is a ->key_size() return value in some instances, or a user-specified ASN.1 length in the case of ecdsa_get_signature_rs().
Weakness: CWE-190
Which versions are affected by CVE-2025-37984?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-37984?
Apply the vendor's patch.
Is CVE-2025-37984 being exploited?
There is no known exploitation of CVE-2025-37984 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2025-37984, DEBIAN-CVE-2025-37984, GHSA-p8pc-4q8f-r225, ROOT-OS-DEBIAN-12-CVE-2025-37984, ROOT-OS-UBUNTU-2204-CVE-2025-37984, ROOT-OS-UBUNTU-2404-CVE-2025-37984 and 1 more.