CVE-2026-90535: Flowise before 3.1.4 Denial of Service via text-to-speech/abort
Flowise versions before 3.1.4 contain an unauthenticated denial of service vulnerability in the /api/v1/text-to-speech/abort endpoint that accepts user-supplied chatflowId and chatId without ownership verification. Attackers can terminate active chatflow predictions for any user by submitting requests with known chatflow and chat identifiers, causing targeted service disruption.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Flowiseto a version that resolves this vulnerability.Fixed in 3.1.4 - Compensating control
If upgrading is not immediately possible, restrict access to the /api/v1/text-to-speech/abort endpoint (e.g., via network ACL/WAF) so unauthenticated requests cannot reach it.
Event History
Frequently Asked Questions
Who can exploit this issue?
An unauthenticated attacker can exploit it if they know valid chatflowId and chatId values for an active chatflow prediction. No ownership verification is performed by the affected endpoint.
What is the operational impact of a successful exploit?
An attacker can terminate active chatflow predictions belonging to other users. This enables targeted service disruption rather than unauthorized access to the prediction data.
Which deployments are affected?
Flowise versions before 3.1.4 are affected. The vulnerable endpoint is exposed at /api/v1/text-to-speech/abort and does not require authentication according to the available information.
How can I determine whether an incident may have occurred?
Review requests to /api/v1/text-to-speech/abort and correlate them with unexpectedly terminated active predictions. Requests using chatflowId and chatId values associated with users other than the requester are relevant indicators, though the endpoint is unauthenticated.