CVE-2025-41086: Vulnerability in the access control system of the GAMS licensing system that allows unlimited valid licenses t

Routine

MEDIUM 6.5REMOTEUPGRADE

CVE-2025-41086 is a medium-severity flaw (CVSS 6.5) affecting gams. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 unrestric

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.2% (top 88%)
CISA exploited list	No
Weakness	CWE-639
Published	2025-12-02
Last modified	2026-10-18

Publisher (CNA): Spanish National Cybersecurity Institute, S.A. (INCIBE) · Vendor: gams

Last updated 2026-10-18 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-12-02 14:16 UTCPublished CVE record published
2026-10-18 18:10 UTCUpdated Record last modified

gams gams UPGRADE

Affected: < 48.7.0 · >= 49.1.0 and < 49.7.0

Fixed in: 48.7.0, 49.7.0

Safe to downgrade to: a release before 49.1.0

1. Check installed version

apt-cache policy gams || rpm -q gams || gams --version

2. UPGRADE to 48.7.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade gams

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade gams

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 49.1.0 (Debian / Ubuntu)

apt-cache madison gams sudo apt install gams=<VERSION_BEFORE_49.1.0> sudo apt-mark hold gams

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list gams sudo dnf downgrade gams-<VERSION_BEFORE_49.1.0> sudo dnf versionlock add gams

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-41086?

gams: upgrade to 48.7.0, 49.7.0. Exact commands for each OS are on this page.

Is CVE-2025-41086 being exploited?

CVE-2025-41086 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-41086 affect?

CVE-2025-41086 affects gams. Severity is medium (CVSS 6.5). 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 th

How urgent is CVE-2025-41086?

Priority 31/100. Remotely exploitable, no login, no user action

References

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