{"id":"CVE-2026-125271","state":"PUBLISHED","title":"AWS API MCP Server Security Policy Bypass via Incorrect Operation Name Normalization","description":"Incorrect normalization of operation names in the custom security policy enforcement in awslabs aws-api-mcp-server before 1.5.1 might allow an actor to execute AWS API operations across AWS services that the operator's security policy was configured to deny or require elicitation for, via calls to operations whose names contain consecutive capital letters.\n\n\n\nTo remediate this issue, users should upgrade to version 1.5.1.","publishedAt":"2026-11-10T16:33:37.925Z","updatedAt":"2026-11-10T16:35:38.381Z","severity":{"score":8.5,"label":"High","version":"4.0","vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","source":"AMZN"},"assigner":"AMZN","products":["AWS aws-api-mcp-server"],"affected":[{"vendor":"AWS","product":"aws-api-mcp-server","defaultStatus":"unaffected","versions":[{"version":"0.2.13","status":"affected","lessThan":"1.5.1","versionType":"custom"}]}],"references":["https://pypi.org/project/awslabs.aws-api-mcp-server/1.5.1/","https://aws.amazon.com/security/security-bulletins/2026-176-aws/","https://github.com/awslabs/mcp/security/advisories/GHSA-4wq9-grf3-qg2p"],"weaknesses":["CWE-1025","CWE-863"],"ingestedAt":"2026-11-10T16:44:07.167Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/125xxx/CVE-2026-125271.json","commit":"309abbe76d3401f08326135c8ee6c392a1692d84","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-125271","state":"PUBLISHED","datePublished":"2026-11-10T16:33:37.925Z","dateUpdated":"2026-11-10T16:35:38.381Z","assignerShortName":"AMZN","assignerOrgId":"ff89ba41-3aa1-4d27-914a-91399e9639e5","dateReserved":"2026-11-09T18:28:57.011Z"},"containers":{"cna":{"title":"AWS API MCP Server Security Policy Bypass via Incorrect Operation Name Normalization","descriptions":[{"lang":"en","value":"Incorrect normalization of operation names in the custom security policy enforcement in awslabs aws-api-mcp-server before 1.5.1 might allow an actor to execute AWS API operations across AWS services that the operator's security policy was configured to deny or require elicitation for, via calls to operations whose names contain consecutive capital letters.\n\n\n\nTo remediate this issue, users should upgrade to version 1.5.1."}],"affected":[{"vendor":"AWS","product":"aws-api-mcp-server","defaultStatus":"unaffected","versions":[{"version":"0.2.13","status":"affected","lessThan":"1.5.1","versionType":"custom"}]}],"references":[{"url":"https://pypi.org/project/awslabs.aws-api-mcp-server/1.5.1/","tags":["release-notes","patch"]},{"url":"https://aws.amazon.com/security/security-bulletins/2026-176-aws/","tags":["vendor-advisory"]},{"url":"https://github.com/awslabs/mcp/security/advisories/GHSA-4wq9-grf3-qg2p","tags":["third-party-advisory"]}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV3_1":{"version":"3.1","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"REQUIRED","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH","baseSeverity":"HIGH","baseScore":7.8,"vectorString":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"}},{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV4_0":{"attackVector":"LOCAL","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"PASSIVE","vulnConfidentialityImpact":"HIGH","subConfidentialityImpact":"NONE","vulnIntegrityImpact":"HIGH","subIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED","version":"4.0","baseSeverity":"HIGH","baseScore":8.5,"vectorString":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-1025","lang":"en","description":"CWE-1025 Comparison using wrong factors","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-863","lang":"en","description":"CWE-863 Incorrect authorization","type":"CWE"}]}],"providerMetadata":{"shortName":"AMZN","orgId":"ff89ba41-3aa1-4d27-914a-91399e9639e5","dateUpdated":"2026-11-10T16:35:38.381Z"},"impacts":[{"capecId":"CAPEC-1","descriptions":[{"lang":"en","value":"CAPEC-1 Accessing Functionality Not Properly Constrained by ACLs"}]}],"cpeApplicability":[{"operator":"OR","nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:aws:aws-api-mcp-server:*:*:*:*:*:*:*:*","versionStartIncluding":"0.2.13","versionEndExcluding":"1.5.1"}]}]}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"Vulnogram 0.5.0"}}}}}