{"id":"CVE-2026-30821","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-30821","generatedAt":"2026-10-31T05:58:59.274Z","title":"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.","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.","published":"2026-03-07T05:16:27.000Z","lastModified":"2026-06-17T10:32:58.000Z","status":"Analyzed","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"4.0","score":8.2,"severity":"HIGH","vector":"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M"},"cwe":["CWE-434"],"affected":["flowiseai/flowise"],"epss":{"score":0.15236,"percentile":0.96758,"date":"2026-10-30","history":[{"date":"2026-09-24","score":0.00898,"percentile":0.5787},{"date":"2026-10-25","score":0.15236,"percentile":0.96737}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"urgent","text":"EPSS puts the probability of exploitation in the next 30 days at 15.2%, higher than 97% of all known CVEs. Patch or mitigate before the next change window."},"changes":[{"kind":"epss","label":"EPSS jump","at":"2026-10-25T00:00:00.000Z","detail":{"to":0.15236,"from":0.00954,"percentile":0.96737},"summary":"EPSS moved from 1.0% to 15.2% probability of exploitation in the next thirty days."}],"references":[{"url":"https://github.com/FlowiseAI/Flowise/releases/tag/flowise%403.0.13","tags":["Product","Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/FlowiseAI/Flowise/security/advisories/GHSA-j8g8-j7fc-43v6","tags":["Exploit","Vendor Advisory"],"source":"security-advisories@github.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-30821","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}