# CVE-2026-9102: Path Traversal in Altium Enterprise Server ComparisonService Allows Arbitrary File Write

> Authenticated users can exploit path traversal in file uploads to write arbitrary files, potentially achieving remote code execution or service takeover.

- **Severity:** Critical 9.4 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 20 May 2026
- **Updated:** 20 May 2026
- **Also known as:** GHSA-396j-87wm-36mh

## What is CVE-2026-9102?

CVE-2026-9102 is a critical path traversal vulnerability in Altium Enterprise Server, published on 20 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A path traversal vulnerability exists in the Altium Enterprise Server ComparisonService due to missing filename sanitization in the Gerber file upload APIs. A regular authenticated workspace user can supply a crafted filename in the multipart Content-Disposition header to escape the intended temporary upload directory and write arbitrary files to any location on the server filesystem.

Because content-controlled files can be written to web-accessible directories, this can be escalated to remote code execution in the context of the service account. It can also be used to overwrite application binaries or configuration files, leading to service takeover or denial of service.

Weakness: CWE-434 (Unrestricted Upload of File with Dangerous Type), CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-9102?


## How do I fix CVE-2026-9102?

No fix has been published for CVE-2026-9102 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-9102 being exploited?

There is no known exploitation of CVE-2026-9102 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-9102 and fix it if it is affected.

What it is: CVE-2026-9102 is a critical path traversal vulnerability in Altium Enterprise Server, published on 20 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-9102 in the wild and no public exploit code.

Affected product: Altium Enterprise Server. 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-2026-9102/ (Markdown: https://insights.sbomify.com/CVE-2026-9102/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-9102
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-9102
- OSV: https://osv.dev/vulnerability/CVE-2026-9102

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-9102/
Summaries are generated and may contain mistakes; the official description above is the record.