# CVE-2025-41086: Authorization bypass in GAMS from GAMS Development Corp.

> Attackers can generate valid licenses to bypass usage restrictions and gain full access to GAMS commercial solvers and models.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 2 Dec 2025
- **Updated:** 2 Dec 2025
- **Also known as:** GHSA-ff5f-4h34-m3c8

## What is CVE-2025-41086?

CVE-2025-41086 is a medium-severity authentication bypass vulnerability in GAMS, published on 2 Dec 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Vulnerability in the access control system of the GAMS licensing system that allows unlimited valid licenses to be generated, bypassing any usage restrictions. The validator uses an insecure checksum algorithm; knowing this algorithm and the format of the license lines, an attacker can recalculate the checksum and generate a valid license to grant themselves full privileges without credentials or access to the source code, allowing them unrestricted access to GAMS's mathematical models and commercial solvers.

Weakness: CWE-639 (Authorization Bypass Through User-Controlled Key)

## Which versions are affected by CVE-2025-41086?

It affects 1 product.


Products: Gams Gams.

## How do I fix CVE-2025-41086?

No fix has been published for CVE-2025-41086 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-41086 being exploited?

There is no known exploitation of CVE-2025-41086 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-41086 and fix it if it is affected.

What it is: CVE-2025-41086 is a medium-severity authentication bypass vulnerability in GAMS, published on 2 Dec 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-2025-41086 in the wild and no public exploit code.

Affected product: GAMS. 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-2025-41086/ (Markdown: https://insights.sbomify.com/CVE-2025-41086/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-41086
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-41086
- OSV: https://osv.dev/vulnerability/CVE-2025-41086

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-41086/
Summaries are generated and may contain mistakes; the official description above is the record.