{"answers":{"affected":"2 open source packages ship an affected version, including elysia. It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-31865 in the wild and no public exploit code.","fix":"Upgrade elysia to 1.4.27 or later.","what":"CVE-2026-31865 is a medium-severity vulnerability in elysiajs elysia, published on 18 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-31865 and fix it if it is affected.\n\nWhat it is: CVE-2026-31865 is a medium-severity vulnerability in elysiajs elysia, published on 18 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-31865 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- elysia (npm): affected all versions; fixed in 1.4.27\n- elysia (npm): affected all versions; fixed in 1.4.27\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-31865/ (Markdown: https://insights.sbomify.com/CVE-2026-31865/index.md)","id":"CVE-2026-31865","markdown":"https://insights.sbomify.com/CVE-2026-31865/index.md","name":"CVE-2026-31865","record":{"aliases":["GHSA-8hq9-phh3-p2wp"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["code_execution","security_bypass"],"network_reachable":"yes","non_default_config":false,"product_category":"Elysia TypeScript framework","requires_auth":"none","summary":"Prototype pollution in Elysia cookie handling allows attackers to override properties, potentially leading to code execution or security bypasses.","user_interaction":"not_required","vuln_class":"other"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"elysia","vendor":"elysiajs"}],"cvss":{"score":6.5,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","version":"3.1"},"cwes":[{"id":"CWE-1321","name":"Improperly Controlled Modification of Object Prototype Attributes"}],"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.","ecosystems":["npm"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"Elysia Cookie Value Prototype Pollution","id":"CVE-2026-31865","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"npm","product":null,"products":[],"type":"other","year":"2026"},"n_packages":2,"n_references":2,"next":{"headline":"Allocation of Resources Without Limits or Throttling in flagd","id":"CVE-2026-31866"},"packages":[{"ecosystem":"npm","fixed":["1.4.27"],"introduced":["0"],"last_affected":[],"package":"elysia","purl":null,"source":"GHSA-8hq9-phh3-p2wp"},{"ecosystem":"npm","fixed":["1.4.27"],"introduced":["0"],"last_affected":[],"package":"elysia","purl":"pkg:npm/elysia","source":"GHSA-8hq9-phh3-p2wp"}],"prev":{"headline":"JumpServer has a Server-Side Template Injection Leading to RCE via YAML Rendering","id":"CVE-2026-31864"},"products":["elysia"],"published":"2026-03-18","related":[{"cvss_score":9.1,"headline":"Elysia vulnerable to prototype pollution with multiple standalone schema validation","id":"CVE-2025-66456","kev_date_added":null,"published":"2025-12-09"},{"cvss_score":7.5,"headline":"Elysia has a string URL format redos","id":"CVE-2026-30837","kev_date_added":null,"published":"2026-03-10"},{"cvss_score":7.5,"headline":"Elysia affected by arbitrary code injection through cookie config","id":"CVE-2025-66457","kev_date_added":null,"published":"2025-12-09"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"yes","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-03-18","vendors":["elysiajs"]},"summary":"Prototype pollution in Elysia cookie handling allows attackers to override properties, potentially leading to code execution or security bypasses.","url":"https://insights.sbomify.com/CVE-2026-31865/"}