# CVE-2025-13912: Potential non-constant time compiled code with Clang LLVM

> LLVM optimizations may break constant-time implementations in wolfSSL, enabling timing side-channel attacks that leak sensitive cryptographic information.

- **Severity:** Low 1.0 (`CVSS:4.0/AV:L/AC:H/AT:P/PR:H/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 11 Dec 2025
- **Updated:** 11 Dec 2025
- **Also known as:** DEBIAN-CVE-2025-13912, GHSA-7582-g6xx-939j, JLSEC-2026-688, UBUNTU-CVE-2025-13912

## What is CVE-2025-13912?

CVE-2025-13912 is a low-severity vulnerability in wolfSSL, published on 11 Dec 2025. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

Multiple constant-time implementations in wolfSSL before version 5.8.4 may be transformed into non-constant-time binary by LLVM optimizations, which can potentially result in observable timing discrepancies and lead to information disclosure through timing side-channel attacks.

Weakness: CWE-203 (Observable Discrepancy)

## Which versions are affected by CVE-2025-13912?


## How do I fix CVE-2025-13912?

Upgrade to a fixed version.

## Is CVE-2025-13912 being exploited?

There is no known exploitation of CVE-2025-13912 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-13912 and fix it if it is affected.

What it is: CVE-2025-13912 is a low-severity vulnerability in wolfSSL, published on 11 Dec 2025. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2025-13912 in the wild and no public exploit code.

Affected product: wolfSSL. 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-2025-13912/ (Markdown: https://insights.sbomify.com/CVE-2025-13912/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-13912
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-13912
- OSV: https://osv.dev/vulnerability/CVE-2025-13912

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-13912/
Summaries are generated and may contain mistakes; the official description above is the record.