{"id":"CVE-2026-27795","state":"PUBLISHED","title":"LangChain Community: redirect chaining can lead to SSRF bypass via RecursiveUrlLoader","description":"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.","publishedAt":"2026-02-25T17:30:01.106Z","updatedAt":"2026-02-25T18:42:52.277Z","severity":{"score":4.1,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:N/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["langchain-ai langchainjs"],"affected":[{"vendor":"langchain-ai","product":"langchainjs","versions":[{"version":"< 1.1.18","status":"affected"}]}],"references":["https://github.com/langchain-ai/langchainjs/security/advisories/GHSA-mphv-75cg-56wg","https://github.com/langchain-ai/langchainjs/security/advisories/GHSA-gf3v-fwqg-4vh7","https://github.com/langchain-ai/langchainjs/pull/9990","https://github.com/langchain-ai/langchainjs/commit/2812d2b2b9fd9343c4850e2ab906b8cf440975ee","https://github.com/langchain-ai/langchainjs/commit/d5e3db0d01ab321ec70a875805b2f74aefdadf9d","https://github.com/langchain-ai/langchainjs/releases/tag/%40langchain%2Fcommunity%401.1.14","https://github.com/langchain-ai/langchainjs/releases/tag/%40langchain%2Fcommunity%401.1.18"],"weaknesses":["CWE-918"],"ingestedAt":"2026-10-29T20:11:31.369Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/27xxx/CVE-2026-27795.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-27795","state":"PUBLISHED","datePublished":"2026-02-25T17:30:01.106Z","dateUpdated":"2026-02-25T18:42:52.277Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-02-24T02:31:33.265Z"},"containers":{"cna":{"title":"LangChain Community: redirect chaining can lead to SSRF bypass via RecursiveUrlLoader","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"langchain-ai","product":"langchainjs","versions":[{"version":"< 1.1.18","status":"affected"}]}],"references":[{"url":"https://github.com/langchain-ai/langchainjs/security/advisories/GHSA-mphv-75cg-56wg","name":"https://github.com/langchain-ai/langchainjs/security/advisories/GHSA-mphv-75cg-56wg","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/langchain-ai/langchainjs/security/advisories/GHSA-gf3v-fwqg-4vh7","name":"https://github.com/langchain-ai/langchainjs/security/advisories/GHSA-gf3v-fwqg-4vh7","tags":["x_refsource_MISC"]},{"url":"https://github.com/langchain-ai/langchainjs/pull/9990","name":"https://github.com/langchain-ai/langchainjs/pull/9990","tags":["x_refsource_MISC"]},{"url":"https://github.com/langchain-ai/langchainjs/commit/2812d2b2b9fd9343c4850e2ab906b8cf440975ee","name":"https://github.com/langchain-ai/langchainjs/commit/2812d2b2b9fd9343c4850e2ab906b8cf440975ee","tags":["x_refsource_MISC"]},{"url":"https://github.com/langchain-ai/langchainjs/commit/d5e3db0d01ab321ec70a875805b2f74aefdadf9d","name":"https://github.com/langchain-ai/langchainjs/commit/d5e3db0d01ab321ec70a875805b2f74aefdadf9d","tags":["x_refsource_MISC"]},{"url":"https://github.com/langchain-ai/langchainjs/releases/tag/%40langchain%2Fcommunity%401.1.14","name":"https://github.com/langchain-ai/langchainjs/releases/tag/%40langchain%2Fcommunity%401.1.14","tags":["x_refsource_MISC"]},{"url":"https://github.com/langchain-ai/langchainjs/releases/tag/%40langchain%2Fcommunity%401.1.18","name":"https://github.com/langchain-ai/langchainjs/releases/tag/%40langchain%2Fcommunity%401.1.18","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":4.1,"baseSeverity":"MEDIUM","confidentialityImpact":"LOW","integrityImpact":"NONE","privilegesRequired":"LOW","scope":"CHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:N/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-918","lang":"en","description":"CWE-918: Server-Side Request Forgery (SSRF)","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-02-25T17:30:01.106Z"},"source":{"advisory":"GHSA-mphv-75cg-56wg","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-02-25T18:42:34.609541Z","id":"CVE-2026-27795","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-02-25T18:42:52.277Z"}}]}}}