Skip to content

LangGraph SDK has unsafe URL path construction

Moderate severity GitHub Reviewed Published May 22, 2026 in langchain-ai/langgraph • Updated Jul 21, 2026

Package

pip langgraph-sdk (pip)

Affected versions

< 0.3.15

Patched versions

0.3.15

Description

Summary

langgraph-sdk constructs HTTP request paths for resource operations by interpolating caller-supplied identifier values into URL templates. Without sanitization of those values, identifiers that contain characters with special meaning in URL paths could cause the resulting request to address a different resource (and potentially a different resource type) than the SDK method's call site indicates. In deployments where the SDK receives identifier values that originate from untrusted sources, this could result in unintended access, modification, or deletion of resources beyond the calling user's authorization scope.

This issue is most consequential in deployments that:

  • forward end-user-supplied values directly into SDK identifier parameters without first validating them against an expected format (such as a UUID), and
  • rely on URL-prefix-based authorization at an upstream layer (reverse proxy, edge gateway, WAF), where the authorization decision is made on the SDK call's intended path rather than on the final delivered request path.

There have no evidence of this behavior being triggered in the wild. This change is intended to reduce the surface available when caller-supplied identifier values originate from untrusted sources.

Affected users / systems

You may be affected if you:

  • use langgraph-sdk (Python) to address resources by identifier, and
  • pass identifier values into SDK methods that originate from end-user input, untrusted third-party callers, or any source that does not validate identifier format before the SDK call.

Applications that validate identifier values (for example, by parsing them as UUIDs and rejecting anything that does not parse) before passing them to SDK methods are not affected. Validated UUIDs round-trip through the SDK request path unchanged.

Impact

  • Potential unintended access, modification, or deletion of resources via SDK methods called for a different resource type, when caller-supplied identifier values are not validated.
  • In deployments with prefix-based authorization at an upstream layer, the authorization decision and the final delivered request path may diverge.
  • Confidentiality: disclosure of resource content beyond the authorization scope of the calling user.
  • Integrity: modification or deletion of resources beyond the authorization scope of the calling user.

Patches / mitigation

The SDK now applies path-segment encoding to identifier values before they are interpolated into request URL templates. After this change, identifier values that contain characters with special meaning in URL paths are transmitted as encoded byte sequences and routed to the resource the SDK method's call site indicates.

Compatibility

Identifier values that match the standard UUID format, or any other format that contains only characters safe to transmit unencoded in URL path segments, round-trip through the SDK request path unchanged. Applications that already validate identifier inputs see no behavioral change.

Operational guidance

  • Validate identifier values (typically as UUIDs) at the boundary where untrusted input enters the application, before passing them to SDK methods.
  • For deployments relying on URL-prefix-based authorization upstream of LangGraph, prefer authorization at the LangGraph server layer or on parsed-and-validated request paths rather than on raw URL prefixes.

LangSmith / hosted deployments note

This issue affects the SDK that runs in caller applications. The LangGraph server runtime, including LangSmith-hosted deployments, receives ordinary HTTP requests on documented routes and is not itself affected by this issue. Applications that consume LangSmith-hosted services via langgraph-sdk and pass untrusted identifier values to SDK methods should upgrade.

First reported by: pucagit (CyStack).

References

@nick-hollon-lc nick-hollon-lc published to langchain-ai/langgraph May 22, 2026
Published by the National Vulnerability Database Jun 17, 2026
Published to the GitHub Advisory Database Jun 25, 2026
Reviewed Jun 25, 2026
Last updated Jul 21, 2026

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(12th percentile)

Weaknesses

Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. Learn more on MITRE.

Incorrect Authorization

The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. Learn more on MITRE.

CVE ID

CVE-2026-48776

GHSA ID

GHSA-w39p-vh2g-g8g5

Source code

Credits

Loading Checking history
See something to contribute? Suggest improvements for this vulnerability.