Flowise: Unauthenticated TTS endpoint accepts arbitrary credential IDs — enables API credit abuse via stored credentials

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

Flowise is a drag & drop user interface to build a customized large language model flow. Prior to 3.1.0, the text-to-speech generation endpoint (POST /api/v1/text-to-speech/generate) is whitelisted (no auth) and accepts a credentialId directly in the request body. When called without a chatflowId, the endpoint uses the provided credentialId to decrypt the stored credential (e.g., OpenAI or ElevenLabs API key) and generate speech. This vulnerability is fixed in 3.1.0.

Source published

23 Apr 2026 19:53:15 UTC

Source modified

23 Apr 2026 20:18:05 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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CVSS 4.0 · 8.2 CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Flowise is a drag & drop user interface to build a customized large language model flow. Prior to 3.1.0, the text-to-speech generation endpoint (POST /api/v1/text-to-speech/generate) is whitelisted (no auth) and accepts a credentialId directly in the request body. When called without a chatflowId, the endpoint uses the provided credentialId to decrypt the stored credential (e.g., OpenAI or ElevenLabs API key) and generate speech. This vulnerability is fixed in 3.1.0.

Source published

Apr 23, 2026, 7:53:15 PM (timezone not stated)

Source modified

Apr 23, 2026, 8:18:05 PM (timezone not stated)

Observed here

28 Oct 2026 05:07:44 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 4.0 · 8.2 CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Flowise is a drag & drop user interface to build a customized large language model flow. Prior to 3.1.0, the text-to-speech generation endpoint (POST /api/v1/text-to-speech/generate) is whitelisted (no auth) and accepts a credentialId directly in the request body. When called without a chatflowId, the endpoint uses the provided credentialId to decrypt the stored credential (e.g., OpenAI or ElevenLabs API key) and generate speech. This vulnerability is fixed in 3.1.0.

Source published

23 Apr 2026 20:16:16 UTC

Source modified

26 Oct 2026 21:10:00 UTC

Observed here

27 Oct 2026 10:10:11 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · [email protected] · Secondary · 8.2 CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS 3.1 · [email protected] · Primary · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

### Summary The text-to-speech generation endpoint (`POST /api/v1/text-to-speech/generate`) is whitelisted (no auth) and accepts a `credentialId` directly in the request body. When called without a `chatflowId`, the endpoint uses the provided `credentialId` to decrypt the stored credential (e.g., OpenAI or ElevenLabs API key) and generate speech. ### Root Cause ```typescript // packages/server/src/controllers/text-to-speech/index.ts:58-64 } else { // Use TTS config from request body provider = bodyProvider credentialId = bodyCredentialId // ← attacker-controlled credential ID voice = bodyVoice model = bodyModel } ``` ### Docker Validation `POST /api/v1/text-to-speech/generate` with arbitrary `credentialId` in body: endpoint processes request, sends SSE `tts_start` event, only fails when credential doesn't exist — proves code path runs without authentication. ### Impact - Use victim's API keys (OpenAI, ElevenLabs, Azure, Google) without authorization - Burn API credits on the victim's account - Generate unlimited speech content at victim's expense - Combined with credential ID leak from Finding 2, this is trivially exploitable ### Suggested Fix Remove the TTS endpoint from `WHITELIST_URLS` or validate that the credential belongs to the chatflow being used: ```typescript // Only allow credentialId when it matches the chatflow's TTS configuration if (!chatflowId) { return res.status(401).json({ message: 'Authentication required' }) } ``` --- ## References - `packages/server/src/controllers/text-to-speech/index.ts` lines 10-162 - `packages/server/src/utils/constants.ts` line 41 (whitelist entry) ## Credits - Shinobi Security - https://github.com/shinobisecurity

Source published

17 Apr 2026 21:35:14 UTC

Source modified

5 May 2026 16:11:36 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS_V4 · CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Publisher rating · HIGH