CVE-2026-30821

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 14.7%, 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, nvd
Elevated
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 15%CVSS: 9.8Exploit: Elevated riskExposed: 0

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

Flowise is a drag & drop user interface to build a customized large language model flow. Prior to version 3.0.13, the /api/v1/attachments/:chatflowId/:chatId endpoint is listed in WHITELIST_URLS, allowing unauthenticated access to the file upload API. While the server validates uploads based on the MIME types defined in chatbotConfig.fullFileUpload.allowedUploadFileTypes, it implicitly trusts the client-provided Content-Type header (file.mimetype) without verifying the file's actual content (magic bytes) or extension (file.originalname). Consequently, an attacker can bypass this restriction by spoofing the Content-Type as a permitted type (e.g., application/pdf) while uploading malicious scripts or arbitrary files. Once uploaded via addArrayFilesToStorage, these files persist in backend storage (S3, GCS, or local disk). This vulnerability serves as a critical entry point that, when chained with other features like static hosting or file retrieval, can lead to Stored XSS, malicious file hosting, or Remote Code Execution (RCE). This issue has been patched in version 3.0.13.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
65(Track*)
EG Risk 65/100SSVC: 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%
Automatability30% × 15%
Action: Watch closely — could escalate to Attend.
EPSS PROB
15%
EPSS %ILE
97%
KEV
Not listed

Published

March 7, 2026

Last Modified

June 17, 2026

Advisory Details (2)

Auto-updated Sep 14, 2026
🔬 Proof of concept available. Patch available. Sources: github_release, github.
github Patch Available🟡 PoC Available

Arbitrary File Upload via MIME Spoofing in FlowiseAI/Flowise · Advisory · FlowiseAI/Flowise · GitHub

https://github.com/FlowiseAI/Flowise/security/advisories/GHSA-j8g8-j7fc-43v6
github_release Patch Available

[email protected]

Patch available: FlowiseAI/Flowise [email protected]

https://github.com/FlowiseAI/Flowise/releases/tag/flowise%403.0.13

Affected Packages

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFixed inDependents
flowise—3.0.13—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 6× in last 7d / 29× 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. 2026-09-18 19:28 UTCEPSS rescore
  2. 2026-09-18 19:27 UTCEPSS rescore
  3. 2026-09-17 19:30 UTCEPSS rescore
  4. 2026-09-16 14:08 UTCEPSS rescore
  5. 2026-09-16 05:15 UTCEPSS rescore
  6. 2026-09-12 15:01 UTCEPSS rescore
  7. 2026-09-11 14:52 UTCEPSS rescore
  8. 2026-09-10 09:34 UTCEPSS rescore
  9. 2026-09-08 22:00 UTCEPSS rescore
  10. 2026-09-07 16:01 UTCEPSS rescore
  11. 2026-09-06 13:47 UTCEPSS rescore
  12. 2026-09-06 13:47 UTCEPSS rescore
  13. 2026-09-04 05:06 UTCEPSS rescore
  14. 2026-09-02 23:29 UTCOSV refresh
  15. 2026-09-02 14:11 UTCEPSS rescore
  16. 2026-09-01 13:53 UTCEPSS rescore
  17. 2026-09-01 04:39 UTCEPSS rescore
  18. 2026-09-01 04:39 UTCEPSS rescore
  19. 2026-08-30 19:17 UTCEPSS rescore
  20. 2026-08-30 01:22 UTCEPSS rescore
  21. 2026-08-28 21:41 UTCEPSS rescore
  22. 2026-08-27 14:25 UTCEPSS rescore
  23. 2026-08-26 14:46 UTCEPSS rescore
  24. 2026-08-25 13:49 UTCEPSS rescore
  25. 2026-08-24 14:17 UTCEPSS rescore
Show 33 more
  1. 2026-08-23 00:19 UTCEPSS rescore
  2. 2026-08-21 23:49 UTCEPSS rescore
  3. 2026-08-20 22:55 UTCEPSS rescore
  4. 2026-08-20 22:55 UTCEPSS rescore
  5. 2026-08-19 17:03 UTCEPSS rescore
  6. 2026-08-18 13:48 UTCEPSS rescore
  7. 2026-08-16 14:56 UTCEPSS rescore
  8. 2026-08-16 12:18 UTCEG score recompute
  9. 2026-08-16 02:14 UTCEPSS rescore
  10. 2026-08-15 01:30 UTCEPSS rescore
  11. 2026-08-14 08:14 UTCEG score recompute
  12. 2026-08-13 22:00 UTCEPSS rescore
  13. 2026-08-12 23:44 UTCEG score recompute
  14. 2026-08-12 13:50 UTCEPSS rescore
  15. 2026-08-11 22:32 UTCEG score recompute
  16. 2026-08-09 17:35 UTCEG score recompute
  17. 2026-08-09 13:46 UTCEPSS rescore
  18. 2026-08-09 07:53 UTCEG score recompute
  19. 2026-08-08 16:37 UTCEPSS rescore
  20. 2026-08-07 19:20 UTCEG score recompute
  21. 2026-08-06 20:23 UTCEG score recompute
  22. 2026-08-06 13:46 UTCEPSS rescore
  23. 2026-08-06 02:22 UTCEG score recompute
  24. 2026-08-05 19:17 UTCEPSS rescore
  25. 2026-08-04 15:10 UTCEPSS rescore
  26. 2026-08-04 01:49 UTCEG score recompute
  27. 2026-08-03 10:36 UTCEPSS rescore
  28. 2026-08-02 18:34 UTCEG score recompute
  29. 2026-08-01 04:16 UTCEPSS rescore
  30. 2026-07-30 16:27 UTCEPSS rescore
  31. 2026-07-30 01:30 UTCEPSS rescore
  32. 2026-07-28 15:36 UTCEPSS rescore
  33. 2026-07-27 13:37 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-30821?
CVE-2026-30821 is a critical vulnerability published on March 7, 2026. Flowise is a drag & drop user interface to build a customized large language model flow. Prior to version 3.0.13, the /api/v1/attachments/:chatflowId/:chatId endpoint is listed in WHITELIST_URLS, allowing unauthenticated access to the file upload API. While the server validates uploads based on the…
When was CVE-2026-30821 disclosed?
CVE-2026-30821 was first published in the National Vulnerability Database on March 7, 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-2026-30821 actively exploited?
CVE-2026-30821 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 15% probability of exploitation in the next 30 days, which ranks it in the top 3.5% of all scored CVEs.
What is the CVSS score of CVE-2026-30821?
CVE-2026-30821 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-30821?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-30821, 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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