CVE-2026-55235

MEDIUMPre-NVD 5.95.9—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.9 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4% (28th percentile of EPSS-scored CVEs). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
5.9EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 5.9Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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.

CVSS v3
5.9
EG Score
5.9MEDIUMmedium confidence
EG Risk
27
EG Risk 27/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity59% × 45%
Exploitation0% × 40%
Automatability0% × 15%
CISA SSVC: Track at every mission impact level.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.4%
EPSS %ILE
28th
KEV
Not listed

CISA SSVCTrack at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 19, 2026

Last Modified

September 30, 2026

Advisory Details (2)

Auto-updated Sep 14, 2026
Patch available. Sources: github.
generic

docs/src/langsmith/agent-server-changelog.mdx at 7b70fbacab21f84d9c6f9848f86cdeb471adbb50 · langchain-ai/docs · GitHub

https://github.com/langchain-ai/docs/blob/7b70fbacab21f84d9c6f9848f86cdeb471adbb50/src/langsmith/agent-server-changelog.mdx
github Patch Available

Relative webhook targets in LangGraph Server can reach in-process routes without authentication · Advisory · langchain-ai/helm · GitHub

https://github.com/langchain-ai/helm/security/advisories/GHSA-2c9q-c2q9-qgqv

Vendor Advisories for CVE-2026-55235(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFix by version rangeDependents
langgraph-api0.0.1 ... 0.9.1 (410 versions)
  • every version up to 0.10.0: fixed in 0.10.0
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 12× in last 7d / 34× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-10-04 23:22 UTCEPSS rescore
  2. 2026-10-03 22:11 UTCEG score recompute
  3. 2026-10-03 14:26 UTCEPSS rescore
  4. 2026-10-02 22:23 UTCEG score recompute
  5. 2026-10-02 17:56 UTCEPSS rescore
  6. 2026-10-01 22:46 UTCEG score recompute
  7. 2026-10-01 19:50 UTCEPSS rescore
  8. 2026-09-30 18:10 UTCEG score recompute
  9. 2026-09-30 15:03 UTCEPSS rescore
  10. 2026-09-30 08:42 UTCEG score recompute
  11. 2026-09-29 15:22 UTCEPSS rescore
  12. 2026-09-29 06:06 UTCEG score recompute
  13. 2026-09-28 13:51 UTCEPSS rescore
  14. 2026-09-28 06:29 UTCEG score recompute
  15. 2026-09-27 13:48 UTCEPSS rescore
  16. 2026-09-27 06:53 UTCEG score recompute
  17. 2026-09-26 15:59 UTCEPSS rescore
  18. 2026-09-24 19:45 UTCEG score recompute
  19. 2026-09-24 14:04 UTCEPSS rescore
  20. 2026-09-23 20:08 UTCEG score recompute
  21. 2026-09-23 17:54 UTCEPSS rescore
  22. 2026-09-22 20:18 UTCEG score recompute
  23. 2026-09-20 20:58 UTCEG score recompute
  24. 2026-09-20 20:16 UTCEPSS rescore
  25. 2026-09-19 21:21 UTCEG score recompute
Show 10 more
  1. 2026-09-18 21:44 UTCEG score recompute
  2. 2026-09-18 19:28 UTCEPSS rescore
  3. 2026-09-17 21:29 UTCEG score recompute
  4. 2026-09-17 19:31 UTCEPSS rescore
  5. 2026-09-16 16:58 UTCEG score recompute
  6. 2026-09-16 15:31 UTCEG score recompute
  7. 2026-09-16 14:08 UTCEPSS rescore
  8. 2026-09-16 05:15 UTCEPSS rescore
  9. 2026-09-14 16:26 UTCEG score recompute
  10. 2026-08-19 19:42 UTCEG score recompute

Related CVEs(same product + same CWE)

Same product

1 shown

PyPI:langgraph-api

Frequently asked(5)

What is CVE-2026-55235?
CVE-2026-55235 is a medium vulnerability published on August 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…
When was CVE-2026-55235 disclosed?
CVE-2026-55235 was first published on August 19, 2026, with the most recent update on September 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55235 actively exploited?
CVE-2026-55235 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (28th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-55235?
CVE-2026-55235 has a CVSS base score of 5.9 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-55235?
A fix for CVE-2026-55235 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-55235 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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