{"id":"CVE-2026-27795","aliases":["GHSA-mphv-75cg-56wg"],"url":"https://o3.security/vulnerability/CVE-2026-27795","summary":"LangChain Community: redirect chaining can lead to SSRF bypass via RecursiveUrlLoader","details":"LangChain is a framework for building LLM-powered applications. Prior to version 1.1.8, a redirect-based Server-Side Request Forgery (SSRF) bypass exists in `RecursiveUrlLoader` in `@langchain/community`. The loader validates the initial URL but allows the underlying fetch to follow redirects automatically, which permits a transition from a safe public URL to an internal or metadata endpoint without revalidation. This is a bypass of the SSRF protections introduced in 1.1.14 (CVE-2026-26019). Users should upgrade to `@langchain/community` 1.1.18, which validates every redirect hop by disabling automatic redirects and re-validating `Location` targets before following them. In this version, automatic redirects are disabled (`redirect: \"manual\"`), each 3xx `Location` is resolved and validated with `validateSafeUrl()` before the next request, and a maximum redirect limit prevents infinite loops.","published":"2026-02-25T17:30:01.106Z","modified":"2026-08-12T03:51:25.064136578Z","cvss":{"score":4.1,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:N/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"@langchain/community","fixedVersion":"1.1.18"}],"fix":{"url":"https://github.com/langchain-ai/langchainjs/commit/2812d2b2b9fd9343c4850e2ab906b8cf440975ee","label":"langchain-ai/langchainjs@2812d2b"},"references":[{"type":"WEB","url":"https://github.com/langchain-ai/langchainjs/releases/tag/%40langchain%2Fcommunity%401.1.14"},{"type":"WEB","url":"https://github.com/langchain-ai/langchainjs/releases/tag/%40langchain%2Fcommunity%401.1.18"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27795.json"},{"type":"ADVISORY","url":"https://github.com/langchain-ai/langchainjs/security/advisories/GHSA-gf3v-fwqg-4vh7"},{"type":"ADVISORY","url":"https://github.com/langchain-ai/langchainjs/security/advisories/GHSA-mphv-75cg-56wg"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-27795"},{"type":"FIX","url":"https://github.com/langchain-ai/langchainjs/commit/2812d2b2b9fd9343c4850e2ab906b8cf440975ee"},{"type":"FIX","url":"https://github.com/langchain-ai/langchainjs/commit/d5e3db0d01ab321ec70a875805b2f74aefdadf9d"},{"type":"FIX","url":"https://github.com/langchain-ai/langchainjs/pull/9990"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:25.064136578Z"}}