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VulnerabilityPublished Updated

CVE-2026-30821: FlowiseAI Flowise · Unrestricted File Upload

Affects FlowiseAI FlowiseSource CVE Database V5

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Not known to be exploited · 15% EPSS · CVSS 8.2 High : upgrade to 3.0.13 soon.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 4.0 base score
8.2High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
15.2% chance of exploitation in 30 days – higher than 96% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 3.0.13
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 7 Mar 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

What to do

Upgrade Flowise and flowiseai/Flowise to 3.0.13.

Affected software

ProductAffectedFixed in
FlowiseAIFlowiseAffected
  • <3.0.13
Fixed in
  • 3.0.13
GitHubflowiseai/Flowisepkg:github/flowiseai/FlowiseOther threatsAffected
  • <3.0.13
Fixed in
  • 3.0.13

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Organizations should immediately upgrade Flowise to version 3.0.13 or later where this vulnerability is patched. Until upgrade, restrict network access to the /api/v1/attachments/:chatflowId/:chatId endpoint to trusted users only, ideally behind authentication and authorization controls. Implement server-side validation of uploaded files by verifying magic bytes and file extensions against allowed types rather than relying on client-supplied MIME types. Employ content scanning tools to detect malicious payloads in uploaded files. Monitor backend storage for unexpected or suspicious files and remove them promptly. Use Web Application Firewalls (WAFs) to detect and block suspicious upload attempts. Conduct regular security audits and penetration tests focusing on file upload functionalities. Educate developers and administrators about secure file handling practices and the risks of trusting client metadata.

Description

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.

References

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