CVE-2026-55255

Langflow exploited vulnerability, confirmed exploited in the wild.

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.

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0.9%chance of exploitation in the next 30 days (EPSS), 59th percentile

7 Juladded to CISA's Known Exploited Vulnerabilities list, 2026

10 Julfederal remediation deadline, already passed

Passedpast the deadline: patch now

CISA's name for it	Langflow Authorization Bypass Through User-Controlled Key Vulnerability
Vendor and product	Langflow · Langflow
Type	exploited vulnerability · CWE-639
Exploited	Confirmed by CISA listed 7 July 2026
Likelihood	scored lower by EPSS, but already confirmed exploited, which outranks any prediction
Deadline	10 July 2026 · already passed
Used in ransomware	Not reported
Advisories	github.com ↗ · www.cisa.gov ↗ · www.cisa.gov ↗ · nvd.nist.gov ↗

What to do

Three steps, in this order

Step 1

Apply the vendor's fix or mitigation; CISA lists only vulnerabilities seen exploited.

Step 2

If you cannot patch now, restrict network access to the affected product.

Step 3

Check for signs of compromise since the date it was added to the list.

CISA's required action	Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

CISA's required action

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

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Questions

CVE-2026-55255 in short

Is CVE-2026-55255 being exploited?

Yes. CISA added CVE-2026-55255 to its Known Exploited Vulnerabilities catalogue on 7 July 2026, which it does only on evidence of exploitation in the wild.

What is the CISA deadline for CVE-2026-55255?

US federal agencies must remediate it by 10 July 2026. Everyone else should treat that date as the latest safe point to patch an internet-facing system.

How likely is CVE-2026-55255 to be exploited in the next 30 days?

FIRST's Exploit Prediction Scoring System gives it 0.9%, the 59th percentile of every CVE it scores.

How do I fix CVE-2026-55255?

Apply the vendor's fix or mitigation; CISA lists only vulnerabilities seen exploited. If you cannot patch now, restrict network access to the affected product. Check for signs of compromise since the date it was added to the list.

Same vendor

Other Langflow vulnerabilities being exploited

CVE	Product	Type	Listed
CVE-2026-0770	Langflow	remote code execution	21 July 2026
CVE-2025-34291	Langflow	remote code execution	21 May 2026
CVE-2026-33017	Langflow	exploited vulnerability	25 March 2026

Sources: CISA Known Exploited Vulnerabilities catalogue (released 10 November 2026) and FIRST EPSS. Page compiled automatically by SAK T.L.M, the threat-intelligence tool of SAK T.E.C, on 13 November 2026.