CVE-2026-55235

MEDIUMPre-NVD 5.95.9
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

Score 5.9 from GitHub Security Advisory (severity: MODERATE) published 2026-08-19. A secondary CVSS source baseline 5.9; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Trending — 4 sources updated this week

Also known asEUVD-2026-77585 (ENISA EUVD) · GHSA-2c9q-c2q9-qgqv (GitHub Security Advisories) · PYSEC-2026-3857 (OSV.dev)Source: ENISA EUVD

5.9EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • 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 27/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity59% × 45%
Impact severity (EG Severity): CVSS 5.9 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.4% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.4%
EPSS %ILE
30th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (5.9): severity, escalated by confirmed exploitation. This CVE's 5.9 is its impact severity (EG Severity), not escalated.

EG Severity
5.9 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.4% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-31). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track 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). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

August 19, 2026

Last Modified

September 30, 2026

Advisory Details (2)

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

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 advisoryMentions a patch (unverified)

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.

Patch Availability(1)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
piplanggraph-api @ 0.10.0 (fixes < 0.10.0)—ghsa

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

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 10× in last 7d / 44× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

  1. 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  2. 2026-11-01 07:44 UTCGHSA enrichmentGHSA-2c9q-c2q9-qgqv · GitHub severity MODERATE · GitHub CVSS 5.9
  3. 2026-11-01 07:44 UTCEG score recompute
  4. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  5. 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  6. 2026-10-30 11:25 UTCOSV refresh
  7. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  8. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  9. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  10. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  11. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  12. 2026-10-25 14:19 UTCEG score recompute
  13. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  14. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  15. 2026-10-22 21:16 UTCEG score recompute
  16. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  17. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  18. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  19. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  20. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  21. 2026-10-18 03:30 UTCEG score recompute
  22. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  23. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  24. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  25. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.4% · 28th percentile
Show 51 more
  1. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  2. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  3. 2026-10-12 15:55 UTCEG score recompute
  4. 2026-10-11 19:39 UTCEG score recompute
  5. 2026-10-11 16:54 UTCEG score recompute
  6. 2026-10-11 14:17 UTCEG score recompute
  7. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  8. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  9. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  10. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  11. 2026-10-08 07:37 UTCEG score recompute
  12. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  13. 2026-10-07 07:33 UTCEG score recompute
  14. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  15. 2026-10-06 07:56 UTCEG score recompute
  16. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  17. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  18. 2026-10-03 22:11 UTCEG score recompute
  19. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  20. 2026-10-02 22:23 UTCEG score recompute
  21. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  22. 2026-10-01 22:46 UTCEG score recompute
  23. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  24. 2026-09-30 18:10 UTCEG score recompute
  25. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  26. 2026-09-30 08:42 UTCEG score recompute
  27. 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  28. 2026-09-29 06:06 UTCEG score recompute
  29. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  30. 2026-09-28 06:29 UTCEG score recompute
  31. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  32. 2026-09-27 06:53 UTCEG score recompute
  33. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  34. 2026-09-24 19:45 UTCEG score recompute
  35. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  36. 2026-09-23 20:08 UTCEG score recompute
  37. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  38. 2026-09-22 20:18 UTCEG score recompute
  39. 2026-09-20 20:58 UTCEG score recompute
  40. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  41. 2026-09-19 21:21 UTCEG score recompute
  42. 2026-09-18 21:44 UTCEG score recompute
  43. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  44. 2026-09-17 21:29 UTCEG score recompute
  45. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  46. 2026-09-16 16:58 UTCEG score recompute
  47. 2026-09-16 15:31 UTCEG score recompute
  48. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  49. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  50. 2026-09-14 16:26 UTCEG score recompute
  51. 2026-08-19 19:42 UTCEG score recomputeFirst assessed: 5.9 MEDIUM

Frequently asked(5)

What is CVE-2026-55235?
CVE-2026-55235 is a medium-severity vulnerability; its CVE record was 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 the CVE record for CVE-2026-55235 published?
The CVE record for CVE-2026-55235 was published on August 19, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 30, 2026; the record at its source may have been updated since.
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 (30th 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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