{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-31865","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-03-09T19:02:25.013Z","datePublished":"2026-03-18T02:50:55.403Z","dateUpdated":"2026-03-18T18:39:09.024Z"},"containers":{"cna":{"title":"Elysia Cookie Value Prototype Pollution","problemTypes":[{"descriptions":[{"cweId":"CWE-1321","lang":"en","description":"CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')","type":"CWE"}]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":6.5,"baseSeverity":"MEDIUM","confidentialityImpact":"LOW","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","version":"3.1"}}],"references":[{"name":"https://github.com/elysiajs/elysia/security/advisories/GHSA-8hq9-phh3-p2wp","tags":["x_refsource_CONFIRM"],"url":"https://github.com/elysiajs/elysia/security/advisories/GHSA-8hq9-phh3-p2wp"},{"name":"https://github.com/elysiajs/elysia/commit/e9d6b1743fa7368ef942dce181f6a089757f6aab","tags":["x_refsource_MISC"],"url":"https://github.com/elysiajs/elysia/commit/e9d6b1743fa7368ef942dce181f6a089757f6aab"}],"affected":[{"vendor":"elysiajs","product":"elysia","versions":[{"version":"< 1.4.27","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-03-18T02:50:55.403Z"},"descriptions":[{"lang":"en","value":"Elysia is a Typescript framework for request validation, type inference, OpenAPI documentation, and client-server communication. Prior to version 1.4.27, an Elysia cookie can be overridden by prototype pollution , eg. `__proto__`. This issue is patched in 1.4.27. As a workaround, use t.Cookie validation to enforce validation value and/or prevent iterable over cookie if possible."}],"source":{"advisory":"GHSA-8hq9-phh3-p2wp","discovery":"UNKNOWN"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-03-18T18:36:47.933361Z","id":"CVE-2026-31865","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-03-18T18:39:09.024Z"}}]}}