CVE-2026-90535

Flowise before 3.1.4 Denial of Service via text-to-speech/abort

Published Sep 12, 2026 CVSS 4.0 · 6.3 Medium EPSS < 1% KEV · Not listed

Description

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.

Analysis

Technical impact

Flowise versions prior to 3.1.4 expose an unauthenticated denial of service vulnerability in the /api/v1/text-to-speech/abort endpoint (CWE-862). The endpoint accepts user-supplied chatflowId and chatId without verifying the caller’s ownership of the associated resources. An attacker can submit crafted requests and terminate active chatflow predictions for any user, leading to targeted service disruption and loss of availability for the affected chat sessions.

Affected Systems

FlowiseAI’s Flowise product is affected. All releases before version 3.1.4 are vulnerable. Clients running these versions should until the vulnerability is remedied (inferred).

Risk and Exploitability

The CVSS score of 6.3 places this issue in the medium severity range. The EPSS score is below 1%, indicating a very low likelihood of exploitation, and the vulnerability is not listed in the CISA KEV catalog. The attack vector is inferred, as no authentication is required to reach the endpoint. An attacker can issue HTTP requests to the abort endpoint and force the termination of any user’s active prediction.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

FlowiseAI

Flowise

unaffected

Version	Status	Constraints
`0`	affected	< 3.1.4
`3.1.4`	unaffected	—

Configuration 1 [-]

cpe:2.3:a:flowiseai:flowise:*:*:*:*:*:*:*:*

No data.

Vendor Product Versions

Flowiseai

Flowise

Version	Status	Scheme	Platform
`[0,3.1.4)`	affected	semver	—
`3.1.4`	unaffected	semver	—

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Apply the vendor released patch that updates Flowise.
If an immediate patch is not feasible, restrict access to the /api/v1/text-to-speech/abort endpoint by firewall rules or reverse‑proxy authentication until the update is applied.
Implement ownership verification for chatflowId and chatId parameters, ensuring that only the creator of a chat or rate‑limiting abort requests in the gateway or load balancer to reduce the impact of potential abuse.

Generated by OpenCVE AI on September 15, 2026 at 18:12 UTC.

Tracking

Advisories

No advisories available

Metrics

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements Present

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact Low

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.482% probability within 30 days)

Exploitation poc

Automatable no

Technical Impact partial

References

Link	Providers
https://github.com/FlowiseAI/Flowise/security/advisories/GHSA-xhxx-56g3-mx2r
https://www.vulncheck.com/advisories/flowise-before-3.1.4-denial-of-service-via-text-to-speech-abort

History

Sep 15, 2026 7:15 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		cvssV3_1 `{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}`

Sep 14, 2026 9:00 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Sep 12, 2026 12:30 PM Description updated. Title updated. First appearance in the feed. Weaknesses updated. Affected versions updated. Affected vendors updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		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.
Title		Flowise before 3.1.4 Denial of Service via text-to-speech/abort
First Time appeared		Flowiseai Flowiseai flowise
Weaknesses		CWE-862
CPEs		cpe:2.3:a:flowiseai:flowise::::::::
Vendors & Products		Flowiseai Flowiseai flowise
References		https://github.com/FlowiseAI/Flowise/security/advisories/GHSA-xhxx-56g3-mx2r https://www.vulncheck.com/advisories/flowise-before-3.1.4-denial-of-service-via-text-to-speech-abort
Metrics		cvssV4_0 `{'score': 6.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N'}`