# CVE-2026-8367: aria2c Improper Certificate Validation

> Attackers can bypass TLS certificate validation by reusing certificates with incorrect Extended Key Usage, enabling man-in-the-middle attacks.

- **Severity:** Medium 4.8 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 13 May 2026
- **Updated:** 13 May 2026
- **Also known as:** DEBIAN-CVE-2026-8367, GHSA-rpx3-3f8j-f6v2, JLSEC-2026-1347, UBUNTU-CVE-2026-8367

## What is CVE-2026-8367?

CVE-2026-8367 is a medium-severity vulnerability in aria2_project aria2c, published on 13 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

aria2c accepts a server certificate with incorrect Extended Key Usage (EKU). If the attackers compromise a certificate (with the associated private key) issued for a different purpose, they may be able to reuse it for TLS server authentication.

Weakness: CWE-295 (Improper Certificate Validation)

## Which versions are affected by CVE-2026-8367?

It affects 1 product.


Products: Aria2 Project Aria2.

## How do I fix CVE-2026-8367?

Upgrade to a fixed version.

## Is CVE-2026-8367 being exploited?

There is no known exploitation of CVE-2026-8367 in the wild and no public exploit code.

## Other vulnerabilities in aria2_project aria2c

- [CVE-2019-3500](https://insights.sbomify.com/CVE-2019-3500/): Information disclosure in n/a (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-8367 and fix it if it is affected.

What it is: CVE-2026-8367 is a medium-severity vulnerability in aria2_project aria2c, published on 13 May 2026. 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-2026-8367 in the wild and no public exploit code.

Affected product: aria2_project aria2c. 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-2026-8367/ (Markdown: https://insights.sbomify.com/CVE-2026-8367/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-8367
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-8367
- OSV: https://osv.dev/vulnerability/CVE-2026-8367

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-8367/
Summaries are generated and may contain mistakes; the official description above is the record.