CVE-2026-40190

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 0.3%, top 76% of all CVEs by exploit prediction. 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, nvd
Elevated
9.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 9.8Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

LangSmith Client SDKs provide SDK's for interacting with the LangSmith platform. Prior to 0.5.18, the LangSmith JavaScript/TypeScript SDK (langsmith) contains an incomplete prototype pollution fix in its internally vendored lodash set() utility. The baseAssignValue() function only guards against the __proto__ key, but fails to prevent traversal via constructor.prototype. This allows an attacker who controls keys in data processed by the createAnonymizer() API to pollute Object.prototype, affecting all objects in the Node.js process. This vulnerability is fixed in 0.5.18.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
60(Track)
EG Risk 60/100SSVC: Track

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
Severity98% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
23.6%
KEV
Not listed

Published

April 10, 2026

Last Modified

July 7, 2026

Advisory Details (1)

Auto-updated Jul 19, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

Prototype Pollution in langsmith-sdk via Incomplete `__proto__` Guard in Internal lodash `set()` · Advisory · langchain-ai/langsmith-sdk · GitHub

Affected: 0.5.18

https://github.com/langchain-ai/langsmith-sdk/security/advisories/GHSA-fw9q-39r9-c252

Affected Packages

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFixed inDependents
langsmith—0.5.18—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 7× 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. 2026-07-23 03:11 UTCEG score recompute▲ 4.20
  2. 2026-07-22 14:08 UTCEPSS rescore
  3. 2026-07-21 15:24 UTCEPSS rescore
  4. 2026-07-20 17:08 UTCEPSS rescore
  5. 2026-07-19 02:29 UTCEPSS rescore
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  8. 2026-07-15 16:57 UTCEPSS rescore
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  15. 2026-07-11 08:27 UTCEPSS rescore
  16. 2026-07-09 19:10 UTCEPSS rescore
  17. 2026-07-08 15:15 UTCEPSS rescore
  18. 2026-07-07 20:14 UTCNVD updateCVSS v3 → 9.8 · severity → CRITICAL
  19. 2026-07-07 13:46 UTCEPSS rescore
  20. 2026-07-06 16:27 UTCEPSS rescore
  21. 2026-07-06 16:27 UTCEPSS rescore
  22. 2026-07-06 02:23 UTCEPSS rescore
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  25. 2026-07-01 15:06 UTCEPSS rescore
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  1. 2026-06-30 23:22 UTCEPSS rescore
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  3. 2026-06-28 14:07 UTCEPSS rescore
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  5. 2026-06-27 03:08 UTCEPSS rescore
  6. 2026-06-25 13:49 UTCEPSS rescore
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  8. 2026-06-24 14:05 UTCEPSS rescore
  9. 2026-06-23 21:33 UTCEPSS rescore
  10. 2026-06-22 14:25 UTCEPSS rescore
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  12. 2026-06-21 14:56 UTCEPSS rescore
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  14. 2026-06-21 01:59 UTCEPSS rescore
  15. 2026-06-19 19:25 UTCEPSS rescore
  16. 2026-06-18 17:52 UTCEPSS rescore
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  18. 2026-06-17 17:53 UTCEPSS rescore
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  20. 2026-06-15 17:49 UTCEPSS rescore
  21. 2026-06-13 23:00 UTCEPSS rescore
  22. 2026-06-12 23:12 UTCEPSS rescore
  23. 2026-06-12 23:12 UTCEPSS rescore
  24. 2026-06-11 14:00 UTCEPSS rescore
  25. 2026-06-10 22:18 UTCEPSS rescore
  26. 2026-06-10 13:22 UTCEPSS rescore
  27. 2026-06-10 13:22 UTCEPSS rescore
  28. 2026-06-08 14:17 UTCEPSS rescore
  29. 2026-06-08 14:17 UTCEPSS rescore
  30. 2026-06-07 15:25 UTCEPSS rescore
  31. 2026-06-07 15:25 UTCEPSS rescore
  32. 2026-06-06 13:47 UTCEPSS rescore
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  36. 2026-06-05 06:10 UTCEPSS rescore
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  38. 2026-06-04 13:12 UTCEPSS rescore
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  40. 2026-06-02 20:13 UTCEPSS rescore
  41. 2026-06-01 13:52 UTCEPSS rescore
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  43. 2026-06-01 13:51 UTCEPSS rescore
  44. 2026-05-31 22:30 UTCEPSS rescore
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  46. 2026-05-31 00:16 UTCEPSS rescore
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  49. 2026-05-29 13:44 UTCEPSS rescore
  50. 2026-05-29 13:44 UTCEPSS rescore
  51. 2026-05-28 13:44 UTCEPSS rescore
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  53. 2026-05-28 13:44 UTCEPSS rescore
  54. 2026-05-27 13:40 UTCEPSS rescore
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  57. 2026-05-26 13:44 UTCEPSS rescore
  58. 2026-05-26 07:18 UTCEPSS rescore
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  60. 2026-05-20 22:38 UTCEPSS rescore
  61. 2026-05-20 22:38 UTCEPSS rescore
  62. 2026-05-20 17:48 UTCEG score recompute
  63. 2026-05-20 11:22 UTCEPSS rescore
  64. 2026-05-20 11:22 UTCEPSS rescore

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-40190?
CVE-2026-40190 is a critical vulnerability published on April 10, 2026. LangSmith Client SDKs provide SDK's for interacting with the LangSmith platform. Prior to 0.5.18, the LangSmith JavaScript/TypeScript SDK (langsmith) contains an incomplete prototype pollution fix in its internally vendored lodash set() utility. The baseAssignValue() function only guards against…
When was CVE-2026-40190 disclosed?
CVE-2026-40190 was first published in the National Vulnerability Database on April 10, 2026, with the most recent update on July 7, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-40190 actively exploited?
CVE-2026-40190 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 23.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-40190?
CVE-2026-40190 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-40190?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-40190, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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