# CVE-2025-27377: Missing Validation of Self-Signed Certificates in Altium Designer Allows Man-in-the-Middle Attacks

> Attackers can intercept traffic and steal credentials or design data due to missing certificate validation in Altium Designer cloud connections.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 22 Jan 2026
- **Updated:** 22 Jan 2026
- **Also known as:** GHSA-xfvg-p8x9-f25q

## What is CVE-2025-27377?

CVE-2025-27377 is a medium-severity vulnerability in Altium Designer, published on 22 Jan 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Altium Designer version 24.9.0 does not validate self-signed server certificates for cloud connections. An attacker capable of performing a man-in-the-middle (MITM) attack could exploit this issue to intercept or manipulate network traffic, potentially exposing authentication credentials or sensitive design data.

Weakness: CWE-295 (Improper Certificate Validation)

## Which versions are affected by CVE-2025-27377?

It affects 1 product.


Products: Altium Designer.

## How do I fix CVE-2025-27377?

No fix has been published for CVE-2025-27377 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-27377 being exploited?

There is no known exploitation of CVE-2025-27377 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-27377 and fix it if it is affected.

What it is: CVE-2025-27377 is a medium-severity vulnerability in Altium Designer, published on 22 Jan 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2025-27377 in the wild and no public exploit code.

Affected product: Altium Designer. 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-2025-27377/ (Markdown: https://insights.sbomify.com/CVE-2025-27377/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-27377
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-27377
- OSV: https://osv.dev/vulnerability/CVE-2025-27377

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-27377/
Summaries are generated and may contain mistakes; the official description above is the record.