# 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.

- **Severity:** High 7.0 (`CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** Yes
- **Published:** 20 May 2025
- **Updated:** 15 Oct 2026
- **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, UBUNTU-CVE-2025-37984

## 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 (Integer Overflow or Wraparound)

## Which versions are affected by CVE-2025-37984?

It affects 1 product.


Products: 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

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-37984 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2025-37984 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-37984/ (Markdown: https://insights.sbomify.com/CVE-2025-37984/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-37984
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-37984
- OSV: https://osv.dev/vulnerability/CVE-2025-37984

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-37984/
Summaries are generated and may contain mistakes; the official description above is the record.