CVE-2025-41086

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.

CVSS v3 6.5 MEDIUM

6.5^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 3.9 / Impact : 2.5

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact LOW

Integrity Impact LOW

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://www.gams.com/latest/docs/RN_51.html	Release Notes
https://www.incibe.es/en/incibe-cert/notices/aviso/authorization-bypass-gams-gams-development-corp	Third Party Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:gams:gams::::::::
	cpe:2.3:a:gams:gams::::::::

History

03 Feb 2026, 17:19

Type	Values Removed	Values Added
First Time		Gams gams
CPE	cpe:2.3:a:gams:access_control_system::::::::	cpe:2.3:a:gams:gams::::::::

30 Jan 2026, 19:05

Type	Values Removed	Values Added
First Time		Gams Gams access Control System
CPE		cpe:2.3:a:gams:access_control_system::::::::
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 6.5
References	~~() https://www.gams.com/latest/docs/RN_51.html -~~	() https://www.gams.com/latest/docs/RN_51.html - Release Notes
References	~~() https://www.incibe.es/en/incibe-cert/notices/aviso/authorization-bypass-gams-gams-development-corp -~~	() https://www.incibe.es/en/incibe-cert/notices/aviso/authorization-bypass-gams-gams-development-corp - Third Party Advisory

02 Dec 2025, 14:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2025-12-02 14:16

Updated : 2026-02-03 17:19

NVD link : CVE-2025-41086

Mitre link : CVE-2025-41086

CVE.ORG link : CVE-2025-41086

JSON object : View

Products Affected

gams

gams

CWE

CWE-639

Authorization Bypass Through User-Controlled Key

{"id": "CVE-2025-41086", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 6.5, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N", "integrityImpact": "LOW", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "LOW"}, "impactScore": 2.5, "exploitabilityScore": 3.9}], "cvssMetricV40": [{"type": "Secondary", "source": "cve-coordination@incibe.es", "cvssData": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 6.9, "Automatable": "NOT_DEFINED", "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "valueDensity": "NOT_DEFINED", "vectorString": "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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "LOW", "integrityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "availabilityRequirement": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "LOW", "confidentialityRequirement": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED"}}]}, "published": "2025-12-02T14:16:25.070", "references": [{"url": "https://www.gams.com/latest/docs/RN_51.html", "tags": ["Release Notes"], "source": "cve-coordination@incibe.es"}, {"url": "https://www.incibe.es/en/incibe-cert/notices/aviso/authorization-bypass-gams-gams-development-corp", "tags": ["Third Party Advisory"], "source": "cve-coordination@incibe.es"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "cve-coordination@incibe.es", "description": [{"lang": "en", "value": "CWE-639"}]}], "descriptions": [{"lang": "en", "value": "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."}], "lastModified": "2026-02-03T17:19:06.673", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:gams:gams:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "164E9A9E-5416-4A53-A5B9-2E79E36A1A06", "versionEndExcluding": "48.7.0"}, {"criteria": "cpe:2.3:a:gams:gams:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "A4E916DD-7173-4A20-BC18-CA056EA771A2", "versionEndExcluding": "49.7.0", "versionStartIncluding": "49.1.0"}], "operator": "OR"}]}], "sourceIdentifier": "cve-coordination@incibe.es"}