CVE-2026-55255

Risk summary

Senserva AI Opinion for CVE-2026-55255

CVE-2026-55255 is a broken access control flaw in Langflow, the open-source tool for building LLM and agent workflows. The specific weakness is authorization bypass through a user-controlled key: an authenticated Langflow user can execute a flow owned by a different user by supplying that victim's flow ID in the request, because the server trusts the caller-supplied identifier instead of checking ownership. This matters beyond a normal privilege issue because Langflow flows can contain components that run code, call external services, and hold secrets and API keys, so executing another user's flow can trigger their integrations and surface their credentials. CISA added it to the Known Exploited Vulnerabilities catalog on 2026-07-07, meaning confirmed active exploitation, and public reporting describes attackers using it for credential harvesting rather than ransomware. The CVSS base score is 9.9 (Critical), while the EPSS probability sits at roughly 1 percent, which is the gap worth understanding: EPSS reflects statistical exploitation likelihood across the whole population and lags real-world events, so a low EPSS number should not override the KEV listing here. The realistic risk is highest for multi-user or shared Langflow deployments where more than one account has flows, since the attacker must first be authenticated.

Do this: Treat this as an in-the-wild bug and act on the KEV status, not the EPSS number. Inventory every Langflow instance, including internal, developer, and proof-of-concept deployments that host AI workflows, and upgrade Langflow to a fixed release per the vendor. If you cannot patch immediately, take exposed Langflow off the public internet and restrict it behind authentication you control, since exploitation requires an authenticated session and network reach. Because the flaw enables running other users' flows, rotate any secrets, API keys, and tokens stored in or reachable by Langflow flows, and review flow execution logs and outbound calls for unauthorized runs during the exposure window given the reported credential harvesting. Federal civilian agencies are bound by the CISA KEV remediation due date, and private organizations should use that same date as their internal deadline.

AI-generated from public data, 2026-07-22. Verify against the vendor advisory before acting.

Senserva AI Opinion and rich prompt for CVE-2026-55255

Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.

Full tracking and change history for CVE-2026-55255

Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.

CISA required action

Federal (BOD 22-01) remediation due date: 2026-07-10 (past due).

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.

Official fix for CVE-2026-55255

Check the vendor's security advisory channel for the patched Langflow versions and workarounds.

Common questions about CVE-2026-55255

Is CVE-2026-55255 actively exploited?

Yes. CVE-2026-55255 was added to the CISA Known Exploited Vulnerabilities (KEV) catalog on 2026-07-07, which means exploitation in the wild has been confirmed, not predicted. Its EPSS 30-day exploitation probability is 29%.

What is the CISA deadline and required action for CVE-2026-55255?

CISA set the federal (BOD 22-01) remediation due date at 2026-07-10, which has passed; treat any unremediated system as overdue. The verbatim 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.

What fixes CVE-2026-55255?

Check the vendor's security advisory for the patched Langflow versions and any workarounds. KEV listing makes this a fix-first item: patch it ahead of higher-CVSS issues nobody is exploiting.

Can I ask my own AI about CVE-2026-55255?

Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2026-55255's key facts: severity, CVSS, EPSS, the KEV date, the CISA due date, and the required action. Copy it into Claude, ChatGPT, or Copilot; the data is refreshed twice a day (5 AM and 3 PM US Central).

More exploited Langflow CVEs

The newest Langflow entries on the CISA KEV catalog:

All Langflow exploited CVEs on one page: Langflow vulnerabilities actively exploited.

Authoritative references