CVE-2026-56277Network attack vector

Cross-origin credential abuse via wildcard TTS header

Published Jun 30, 2026 · Updated Jun 30, 2026

Origin validation error in Flowise before 3.1.2 allows remote attackers to trigger TTS generation through cross-origin requests. The TTS controller hardcodes Access-Control-Allow-Origin to * instead of honoring the server-wide CORS policy. Reachability requires a browser with access to the Flowise instance and stored TTS credentials to load an attacker-controlled webpage, which can consume those credentials to generate speech.

CVSS severity6.9
Medium
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Origin validation error in Flowise before 3.1.2 allows remote attackers to trigger TTS generation through cross-origin requests. The TTS controller hardcodes Access-Control-Allow-Origin to * instead of honoring the server-wide CORS policy. Reachability requires a browser with access to the Flowise instance and stored TTS credentials to load an attacker-controlled webpage, which can consume those credentials to generate speech.

The record

CVE
CVE-2026-56277
Published
Jun 30, 2026
Updated
Jun 30, 2026
Vendor
FlowiseAI
Product
Flowise
Classifications
CWE-346, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 30, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 30, 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 <3.1.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

FlowiseAI · Flowiseversion=0 <3.1.2

Published CVSS scores

6.9VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
6.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A: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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-346Origin Validation Error
T1189Drive-by Compromise

Public exploit references

No public exploit references are available in this record.

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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