{"cve":"CVE-2026-31865","nvd":{"published":"2026-03-18T04:17:19.393","modified":"2026-06-17T10:34:39.547","status":"Analyzed","description":"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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","score":5.3},"cwes":["CWE-1321"],"references":["https://github.com/elysiajs/elysia/commit/e9d6b1743fa7368ef942dce181f6a089757f6aab","https://github.com/elysiajs/elysia/security/advisories/GHSA-8hq9-phh3-p2wp"],"products":["elysiajs:elysia"],"source":"nvd","synced_at":"2026-10-19T22:26:19.218427112+00:00"},"epss":{"cve":"CVE-2026-31865","score":0.00241,"percentile":0.15227,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-8hq9-phh3-p2wp","url":"https://osv.dev/vulnerability/GHSA-8hq9-phh3-p2wp","summary":"Elysia Cookie Value Prototype Pollution","modified":"2026-03-19T19:17:47.117772Z","packages":[{"ecosystem":"npm","name":"elysia","purl":"pkg:npm/elysia","ranges":["<1.4.27"],"fixed":["1.4.27"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}