{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-65957","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-07-23T18:15:14.579Z","datePublished":"2026-11-11T20:36:21.626Z","dateUpdated":"2026-11-11T20:36:21.626Z"},"containers":{"cna":{"title":"Helio: Dashboard sideband CORS origin allowlist matches hostnames by prefix, admitting attacker-controlled origins in open mode","problemTypes":[{"descriptions":[{"cweId":"CWE-346","lang":"en","description":"CWE-346: Origin Validation Error","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-942","lang":"en","description":"CWE-942: Permissive Cross-domain Security Policy with Untrusted Domains","type":"CWE"}]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"LOW","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":6.9,"baseSeverity":"MEDIUM","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","version":"4.0"}}],"references":[{"name":"https://github.com/gethelio/helio/security/advisories/GHSA-2c3r-q7gv-hp2m","tags":["x_refsource_CONFIRM"],"url":"https://github.com/gethelio/helio/security/advisories/GHSA-2c3r-q7gv-hp2m"},{"name":"https://github.com/gethelio/helio/pull/121","tags":["x_refsource_MISC"],"url":"https://github.com/gethelio/helio/pull/121"},{"name":"https://github.com/gethelio/helio/commit/4ca8329c38b0edbc5e4d782a4e3b0cfc5cd7782e","tags":["x_refsource_MISC"],"url":"https://github.com/gethelio/helio/commit/4ca8329c38b0edbc5e4d782a4e3b0cfc5cd7782e"},{"name":"https://github.com/gethelio/helio/releases/tag/v0.8.0","tags":["x_refsource_MISC"],"url":"https://github.com/gethelio/helio/releases/tag/v0.8.0"}],"affected":[{"vendor":"gethelio","product":"helio","versions":[{"version":"< 0.8.0","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-11-11T20:36:21.626Z"},"descriptions":[{"lang":"en","value":"Helio is an MCP proxy that sits between AI agents and the tools they use. Prior to version 0.8.0, the dashboard sideband (default 127.0.0.1:3100) validated CORS request origins by matching the hostname against a private-network string prefix (10., 172.16.–172.31., 192.168.) rather than validating an IP address. A public DNS name such as 192.168.attacker.com, 10.evil.io, or 172.16.pwn.example also satisfies that prefix, so the proxy echoed the attacker origin in Access-Control-Allow-Origin. This issue has been patched in version 0.8.0."}],"source":{"advisory":"GHSA-2c3r-q7gv-hp2m","discovery":"UNKNOWN"}}}}