CVE-2026-55423: Langflow Session Invalidation Flaw—Impact, Patch & Detection

Technical summary

CVE-2026-55423 involves improper session termination in Langflow prior to version 1.7.0. The logout function fails to invalidate the active session, leaving authentication state intact. This is classified as CWE-613 (Insufficient Session Expiration). The vulnerability requires physical or logical access to an already-authenticated session and does not allow privilege escalation or denial of service, but does enable confidentiality and integrity violations through unauthorized access to user data and operations.

Business impact

Organizations deploying Langflow for AI workflow automation face credential persistence risks, particularly in environments where multiple team members share workstations or where AI agents handle sensitive business logic. Unauthorized session continuation could lead to unauthorized data access, modification of AI workflows, execution of agents with compromised intent, and potential compliance violations if the platform processes regulated data. The impact scales with the sensitivity of workflows and data the platform orchestrates.

Affected systems

Langflow versions prior to 1.7.0 are affected. The vulnerability is resolved in version 1.7.0 and later. Organizations running Langflow should verify their current version against their deployment inventory. Cloud-hosted and self-hosted instances are equally vulnerable if not updated.

Exploitability

Exploitation requires the attacker to have physical or network-adjacent access to a Langflow session that is already authenticated. The CVSS vector AV:P indicates proximity/physical access is needed. Once a user clicks logout without the attacker re-authenticating, the attacker would need to regain access to that same browser or client session to maintain the connection. This is not a remote unauthenticated attack; it targets a specific post-logout window, making it a medium-severity issue rather than critical. Real-world risk depends on operational security practices around shared terminals.

Remediation

Upgrade to Langflow version 1.7.0 or later. This version includes proper session invalidation on logout. Organizations should prioritize patching systems in shared-access environments or those processing sensitive AI workflows. Verify the upgrade path with your Langflow deployment documentation to ensure no workflow or configuration loss.

Patch guidance

Update Langflow to version 1.7.0 or newer. Review the vendor's release notes and migration guidance at the official Langflow repository to confirm compatibility with your current workflows and dependencies. Test the upgrade in a staging environment before deploying to production, particularly if you have customized AI agents or integrations. After patching, verify that logout properly terminates sessions by checking that re-accessing the application requires re-authentication.

Detection guidance

Monitor Langflow deployment version numbers in your inventory. Check application logs for session lifecycle events to identify logout attempts and subsequent access patterns without new authentication events. In shared-access scenarios, alert on cases where the same session ID persists across multiple user identities or IP addresses after a logout request. Consider implementing session monitoring dashboards that show active session counts and lifetimes. Verify that session cookies or tokens are being cleared from client storage on logout.

Why prioritize this

This is a medium-severity vulnerability (CVSS 6.1) that should be addressed promptly but not as an emergency. It requires proximity/physical access or a specific operational scenario (shared workstations, multi-user systems) to be exploited. However, organizations with shared Langflow instances or those processing sensitive workflows should treat this as higher priority. The fix is straightforward (upgrade to 1.7.0), and the vulnerability has not been weaponized or added to the CISA KEV catalog, indicating low active exploitation in the wild at this time.

Risk score, explained

The CVSS 6.1 MEDIUM score reflects the combination of proximity-based access requirement (AV:P), low attack complexity, no privilege escalation needed, but significant confidentiality and integrity impact once exploited. The score appropriately captures that this is a real risk in multi-user environments but not a widespread, remotely-exploitable crisis. Organizations in single-user or strictly controlled access scenarios may face lower practical risk.

Frequently asked questions