# CVE-2025-9231: Timing side-channel in SM2 algorithm on 64 bit ARM

> A timing side-channel in OpenSSL's SM2 implementation on 64-bit ARM may allow attackers to recover private keys via remote timing measurements.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 30 Sep 2025
- **Updated:** 14 Jul 2026
- **Also known as:** ALPINE-CVE-2025-9231, BELL-CVE-2025-9231, DEBIAN-CVE-2025-9231, ECHO-2b7e-78d4-c817, GHSA-9mrx-mqmg-gwj9, JLSEC-2026-267, MINI-4x56-859r-prjq, MINI-f394-p673-w5hp, UBUNTU-CVE-2025-9231

## What is CVE-2025-9231?

CVE-2025-9231 is a medium-severity vulnerability in OpenSSL, published on 30 Sep 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Issue summary: A timing side-channel which could potentially allow remote
recovery of the private key exists in the SM2 algorithm implementation on 64 bit
ARM platforms.

Impact summary: A timing side-channel in SM2 signature computations on 64 bit
ARM platforms could allow recovering the private key by an attacker..

While remote key recovery over a network was not attempted by the reporter,
timing measurements revealed a timing signal which may allow such an attack.

OpenSSL does not directly support certificates with SM2 keys in TLS, and so
this CVE is not relevant in most TLS contexts.  However, given that it is
possible to add support for such certificates via a custom provider, coupled
with the fact that in such a custom provider context the private key may be
recoverable via remote timing measurements, we consider this to be a Moderate
severity issue.

The FIPS modules in 3.5, 3.4, 3.3, 3.2, 3.1 and 3.0 are not affected by this
issue, as SM2 is not an approved algorithm.

Weakness: CWE-385 (Covert Timing Channel)

## Which versions are affected by CVE-2025-9231?


## How do I fix CVE-2025-9231?

Apply the vendor's patch.

## Is CVE-2025-9231 being exploited?

There is no known exploitation of CVE-2025-9231 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-9231 and fix it if it is affected.

What it is: CVE-2025-9231 is a medium-severity vulnerability in OpenSSL, published on 30 Sep 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-9231 in the wild and no public exploit code.

Affected product: OpenSSL. 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-2025-9231/ (Markdown: https://insights.sbomify.com/CVE-2025-9231/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-9231
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-9231
- OSV: https://osv.dev/vulnerability/CVE-2025-9231

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-9231/
Summaries are generated and may contain mistakes; the official description above is the record.