CVE-2026-33309

CRITICALPre-NVD 9.99.9—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.9 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 11.1%, top 4% 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, secondary
Elevated
9.9EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 11%CVSS: 9.9Exploit: Elevated riskExposed: 0

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

Langflow is a tool for building and deploying AI-powered agents and workflows. Versions 1.2.0 through 1.8.1 have a bypass of the patch for CVE-2025-68478 (External Control of File Name), leading to the root architectural issue within LocalStorageService remaining unresolved. Because the underlying storage layer lacks boundary containment checks, the system relies entirely on the HTTP-layer ValidatedFileName dependency. This defense-in-depth failure leaves the POST /api/v2/files/ endpoint vulnerable to Arbitrary File Write. The multipart upload filename bypasses the path-parameter guard, allowing authenticated attackers to write files anywhere on the host system, leading to Remote Code Execution (RCE). Version 1.9.0 contains an updated fix.

CVSS v3
9.9
EG Score
9.9(medium)
EG Risk
61(Track*)
EG Risk 61/100SSVC: 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
Severity99% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Watch closely — could escalate to Attend.
EPSS PROB
11%
EPSS %ILE
96%
KEV
Not listed

Published

March 19, 2026

Last Modified

June 17, 2026

Advisory Details (1)

Auto-updated Aug 24, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

Arbitrary File Write (RCE) via v2 API · Advisory · langflow-ai/langflow · GitHub

https://github.com/langflow-ai/langflow/security/advisories/GHSA-g2j9-7rj2-gm6c

Vendor Advisories for CVE-2026-33309(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 rangeFixed inDependents
langflow1.2.0 ... 1.8.4 (41 versions)1.9.0—

Weakness Classification(4)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 37× 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.

Showing the most recent 100 of 113 total refreshes for this CVE.

  1. 2026-08-26 14:46 UTCEPSS rescore
  2. 2026-08-25 13:49 UTCEPSS rescore
  3. 2026-08-24 14:17 UTCEPSS rescore
  4. 2026-08-23 00:19 UTCEPSS rescore
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  11. 2026-08-16 14:56 UTCEPSS rescore
  12. 2026-08-16 11:10 UTCEG score recompute
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  19. 2026-08-11 21:28 UTCEG score recompute
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  22. 2026-08-09 17:34 UTCEG score recompute
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  24. 2026-08-09 06:54 UTCEG score recompute
  25. 2026-08-08 16:37 UTCEPSS rescore
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  1. 2026-08-07 17:24 UTCEG score recompute
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  3. 2026-08-06 13:46 UTCEPSS rescore
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  5. 2026-08-05 19:17 UTCEPSS rescore
  6. 2026-08-04 15:10 UTCEPSS rescore
  7. 2026-08-04 10:38 UTCEPSS rescore
  8. 2026-08-02 16:35 UTCEG score recompute
  9. 2026-08-02 02:27 UTCEPSS rescore
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  11. 2026-07-30 16:28 UTCEPSS rescore
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  21. 2026-07-23 03:09 UTCEG score recompute
  22. 2026-07-22 14:08 UTCEPSS rescore
  23. 2026-07-21 15:24 UTCEPSS rescore
  24. 2026-07-20 17:08 UTCEPSS rescore
  25. 2026-07-19 14:31 UTCEPSS rescore
  26. 2026-07-19 02:29 UTCEPSS rescore
  27. 2026-07-18 10:04 UTCEPSS rescore
  28. 2026-07-17 14:59 UTCOSV refresh
  29. 2026-07-16 17:03 UTCEPSS rescore
  30. 2026-07-15 16:57 UTCEPSS rescore
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  32. 2026-07-15 02:00 UTCEPSS rescore
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  37. 2026-07-12 05:46 UTCEPSS rescore
  38. 2026-07-11 08:27 UTCEPSS rescore
  39. 2026-07-09 19:10 UTCEPSS rescore
  40. 2026-07-08 15:15 UTCEPSS rescore
  41. 2026-07-07 13:46 UTCEPSS rescore
  42. 2026-07-06 16:27 UTCEPSS rescore
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  44. 2026-07-06 02:23 UTCEPSS rescore
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  47. 2026-07-04 06:31 UTCEPSS rescore
  48. 2026-07-01 15:06 UTCEPSS rescore
  49. 2026-06-30 23:22 UTCEPSS rescore
  50. 2026-06-29 13:23 UTCOSV refresh
  51. 2026-06-28 14:07 UTCEPSS rescore
  52. 2026-06-28 14:07 UTCEPSS rescore
  53. 2026-06-28 04:56 UTCEPSS rescore
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  55. 2026-06-27 03:08 UTCEPSS rescore
  56. 2026-06-25 13:49 UTCEPSS rescore
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  58. 2026-06-24 14:05 UTCEPSS rescore
  59. 2026-06-23 21:33 UTCEPSS rescore
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  61. 2026-06-22 14:25 UTCEPSS rescore
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  63. 2026-06-21 14:56 UTCEPSS rescore
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  65. 2026-06-21 01:59 UTCEPSS rescore
  66. 2026-06-19 19:25 UTCEPSS rescore
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  68. 2026-06-18 17:52 UTCEPSS rescore
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  71. 2026-06-16 17:52 UTCEPSS rescore
  72. 2026-06-15 17:49 UTCEPSS rescore
  73. 2026-06-14 23:18 UTCEPSS rescore
  74. 2026-06-13 23:00 UTCEPSS rescore
  75. 2026-06-12 23:12 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-33309?
CVE-2026-33309 is a critical vulnerability published on March 19, 2026. Langflow is a tool for building and deploying AI-powered agents and workflows. Versions 1.2.0 through 1.8.1 have a bypass of the patch for CVE-2025-68478 (External Control of File Name), leading to the root architectural issue within LocalStorageService remaining unresolved. Because the underlying…
When was CVE-2026-33309 disclosed?
CVE-2026-33309 was first published in the National Vulnerability Database on March 19, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-33309 actively exploited?
CVE-2026-33309 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 11% probability of exploitation in the next 30 days, which ranks it in the top 4.4% of all scored CVEs.
What is the CVSS score of CVE-2026-33309?
CVE-2026-33309 has a CVSS v3 base score of 9.9 (NVD).
How do I remediate CVE-2026-33309?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-33309, 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.

Dependency Blast Radius

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