CVE-2026-90535Public exploitNetwork attack vectorHinoki check available

Prediction interruption via unauthorized abort-controller lookup

Published Sep 12, 2026 · Updated Sep 12, 2026

Missing authorization in Flowise before 3.1.4 allows remote attackers to interrupt active chatflow predictions via the TTS abort API. The whitelisted /api/v1/text-to-speech/abort handler builds a main AbortController key from untrusted chatflowId and chatId values and aborts it without verifying session ownership. Exploitation requires a valid chatflow ID and an active session's chat ID; repeated requests can keep that prediction session unusable without crashing the server.

CVSS severity6.3
Medium
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Missing authorization in Flowise before 3.1.4 allows remote attackers to interrupt active chatflow predictions via the TTS abort API. The whitelisted /api/v1/text-to-speech/abort handler builds a main AbortController key from untrusted chatflowId and chatId values and aborts it without verifying session ownership. Exploitation requires a valid chatflow ID and an active session's chat ID; repeated requests can keep that prediction session unusable without crashing the server.

The record

CVE
CVE-2026-90535
Published
Sep 12, 2026
Updated
Sep 12, 2026
Vendor
FlowiseAI
Product
Flowise
Classifications
CWE-862, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 12, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 12, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <3.1.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

FlowiseAI · Flowiseversion=0 <3.1.4

Published CVSS scores

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

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-862Missing Authorization
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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