Missing Authorization in Flowise - CVE-2026-90535
Published: August 31, 2026 / Updated: September 14, 2026
Vulnerability identifier: #VU146337
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-90535
CWE-ID: CWE-862
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to missing authorization in the /api/v1/text-to-speech/abort endpoint when handling crafted abort requests with user-supplied chatflowId and chatId values. A remote attacker can send a specially crafted request to cause a denial of service.
The issue can terminate an in-progress chatflow prediction for another user and may also disrupt client-side UI state through server-sent events.
Affected software
Flowise
How to mitigate CVE-2026-90535
Install security update from vendor's website.
Flowise - update to 3.1.4