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CVE-2026-55255

Langflow: IDOR Vulnerability in `/api/v1/responses` Endpoint Allows Authenticated Attackers to Access Another User's Flow

Published: Jun 23, 2026Updated: Jun 24, 2026 Sources: CVE List NVDCWE-639
9.9CRITICAL
NVD MITRE
EPSS Score
0.2%
Top 85.8%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
Not available

Description

Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.2, an Insecure Direct Object Reference (IDOR) vulnerability in /api/v1/responses endpoint allows an authenticated attacker to execute any flow belonging to another user by specifying the victim's flow ID in the request. This vulnerability is fixed in 1.9.2.

In plain language

AI Worth attention

In Langflow, an authenticated attacker can use another user’s flow ID to run that other flow via the /api/v1/responses endpoint—this is serious if you have untrusted users who can log in, and you should upgrade to 1.9.2.

Executive summary

CVE-2026-55255 is an IDOR in Langflow’s /api/v1/responses endpoint that lets authenticated attackers access and execute another user’s flow by supplying the victim’s flow ID in their request; fixed in langflow 1.9.2.

If affected, business impact
Unauthorized execution of other flowsSensitive data exposureCross-user account compromise riskOperational disruption from mis-runs

What to do now

  1. Check your Langflow version and confirm whether you are running a version older than 1.9.2.
  2. If you are older than 1.9.2, plan an upgrade to Langflow 1.9.2 as soon as possible.
  3. Review who has accounts that can access Langflow and treat any “guest” or contractor accounts as untrusted unless needed.
  4. After upgrading, verify that requests to /api/v1/responses only allow access to flows owned by the logged-in user.
Patch / advisory Usually a quick update

CVSS Vector Breakdown

AV:NAC:LPR:LUI:NS:CC:HI:HA:L
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:LPrivileges Required
Low
UI:NUser Interaction
None
Scope
S:CScope
Changed
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:LAvailability
Low
Open in CVSS calculator →

Weaknesses

CWE-639

Affected Products

langflow-ai
commercial
langflowSaaS
AI / ML
langflow
commercialaka langflow desktop, langflow-base
langflowSaaS
AI / ML / ai-agent-tooling

Exploitability

Official Patch Available
Is your org exposed to CVE-2026-55255?We can run the check for you — a free external exposure review, no install. Check my exposure

Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

1 technique
Initial Access
View detailed technique mapping

References

https://github.com/langflow-ai/langflow/security/advisories/GHSA-qrpv-q767-xqq2
github.com
https://github.com/langflow-ai/langflow/pull/12832
github.com
News mentions
2

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