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TI-2026-20818 Aliases CVE-2026-25750

LangSmith Studio has URL Parameter Injection Vulnerability that Enables Token Theft via Malicious baseUrl

Priority MEDIUM 43CWE-74Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Active
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
High · High · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

Langchain Helm Charts are Helm charts for deploying Langchain applications on Kubernetes. Prior to langchain-ai/helm version 0.12.71, a URL parameter injection vulnerability existed in LangSmith Studio that could allow unauthorized access to user accounts through stolen authentication tokens. The vulnerability affected both LangSmith Cloud and self-hosted deployments. Authenticated LangSmith users who clicked on a specially crafted malicious link would have their bearer token, user ID, and workspace ID transmitted to an attacker-controlled server. With this stolen token, an attacker could impersonate the victim and access any LangSmith resources or perform any actions the user was authorized to perform within their workspace. The attack required social engineering (phishing, malicious links in emails or chat applications) to convince users to click the crafted URL. The stolen tokens expired after 5 minutes, though repeated attacks against the same user were possible if they could be convinced to click malicious links multiple times. The fix in version 0.12.71 implements validation requiring user-defined allowed origins for the baseUrl parameter, preventing tokens from being sent to unauthorized servers. No known workarounds are available. Self-hosted customers must upgrade to the patched version.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00348 28th percentileScored 2026-11-07
Fix Fixed helm (langchain-ai): 0.12.71

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
langchain-aihelmbefore 0.12.710.12.71Patch availableCNA
  • helm Vendorlangchain-ai Affected before 0.12.71 Fixed in 0.12.71 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:langchain:langsmith:*:*:*:*:*:kubernetes:*:*before 0.12.71Vulnerablelangchain-ai
  • cpe:2.3:a:langchain:langsmith:*:*:*:*:*:kubernetes:*:* Versions before 0.12.71 Vulnerable ·langchain-ai

Remediation

  • Fix · CNA helm (langchain-ai) Fixed in 0.12.71

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-25750

References

  • TI-2026-29004 Prototype pollution in langchain-ai langsmith-sdk CVSS 3.1CRITICAL 9.8

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences