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CVE-2026-55255

Langflow Authorization Bypass Through User-Controlled Key

8.4 HIGHActively exploited (CISA KEV)Public exploitEPSS 0.89%
  1. Published23 Jun 2026
  2. Added to CISA KEV7 Jul 2026
  3. Remediation due10 Jul 2026
Actively exploited (CISA KEV)

Langflow contains an authorization bypass through user-controlled key vulnerability which allows an authenticated attacker to execute any flow belonging to another user by specifying the victim's flow ID in the request.

Added to KEV: 7 Jul 2026Federal remediation due: 10 Jul 2026

Description

Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.1, 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 1.9.1.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityHigh
Privileges requiredLow
User interactionNone
ScopeChanged
ConfidentialityHigh
IntegrityHigh
AvailabilityLow
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L

Affected products

Langflow< 1.9.1

Remediation

Fixed in
Langflow≥ 1.9.1

References

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Frequently asked

Is CVE-2026-55255 being actively exploited?

Yes. CVE-2026-55255 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 7 Jul 2026.

How severe is CVE-2026-55255?

CVE-2026-55255 has a CVSS 3.1 base score of 8.4, rated high. EPSS estimates a 0.89% probability of exploitation.

Which products are affected by CVE-2026-55255?

Affected products include Langflow.

How do I fix CVE-2026-55255?

Upgrade affected software to a fixed version, for example Langflow 1.9.1 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-55255 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, Secuno flags any affected asset as top-priority automatically. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.