Answer in brief
CVE-2026-55235 records a Medium severity (CVSS 5.9) vulnerability in langgraph-api: Relative webhook targets in LangGraph Server can reach in-process routes without authentication. The current sources do not mark it as known exploited. The current feed maps langchain-ai/langgraph-api (generic), langgraph-api (pip), langgraph-api (pypi). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.9. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps langchain-ai/langgraph-api (generic), langgraph-api (pip), langgraph-api (pypi). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| langchain-ai/langgraph-apigeneric | < 0.10.0 | Not reported |
| langgraph-apipip | <0.10.0 | 0.10.0 |
| langgraph-apipypi | >=0 <0.10.0 | 0.10.0 |
Published upstream
Sep 14, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 14, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 19, 2026
langgraph-api implements the LangGraph API for rapid development and testing. Prior to 0.10.0, langgraph-api permits a run or cron to specify a relative webhook target that is delivered through an in-process loopback transport, and the authentication middleware treats that transport as internal without applying the authentication context used for external requests. In deployments that rely on per-user authorization to separate threads and runs, an authenticated user can direct a webhook to the server's own thread and run routes, allowing creation of a run on or modification of another user's thread and limited incorporation of the targeted thread's metadata into the created run record. The affected path requires webhook targets and per-user authorization boundaries; deployments that deliberately re-enable loopback delivery should restrict it to controlled same-process routes because those webhooks remain unauthenticated. This issue is fixed in version 0.10.0.
Quoted source text, attributed separately from HOL analysis.