CVE-2026-27795
MEDIUMCVE-2026-27795 is a medium-severity (CVSS 4.1) Server-Side Request Forgery (SSRF) vulnerability in @langchain/community. O3 Security confirms whether CVE-2026-27795 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
LangChain Community: redirect chaining can lead to SSRF bypass via RecursiveUrlLoader
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
@langchain/communitynpmDescription
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 Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @langchain/community | all versions | 1.1.18 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @langchain/community. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update @langchain/community to 1.1.18 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-27795 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-27795 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-27795. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-27795 in your dependencies?
O3 detects CVE-2026-27795 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.