What is the CVSS score of EUVD-2026-38516?

EUVD-2026-38516 has a CVSS 3.1 base score of 6.1 (Medium). CVSS vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N. EPSS exploitation probability: 0.2%.

Is there a patch available for EUVD-2026-38516?

Yes, a patch is available for EUVD-2026-38516. Update the affected software to the latest version immediately.

Langflow EUVD-2026-38516

| CVE-2026-55423 MEDIUM

Insufficient Session Expiration (CWE-613)

2026-06-19 https://github.com/langflow-ai/langflow

GHSA-7hw8-6q6r-4276

Information Disclosure

6.1

CVSS 3.1 · Vendor: https://github.com/langflow-ai/langflow

Severity by source

Vendor (https://github.com/langflow-ai/langflow) PRIMARY

6.1 MEDIUM

AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

vuln.today AI

6.1 MEDIUM

Physical access required (AV:P) for shared-browser exploitation; no attacker credentials needed (PR:N); full session hijack yields high C and I with no availability impact.

3.1 AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

4.0 AV:P/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

Primary rating from Vendor (https://github.com/langflow-ai/langflow).

CVSS VectorVendor: https://github.com/langflow-ai/langflow

Attack Vector

Physical

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

None

Lifecycle Timeline

Source Code Evidence Fetched

Jun 19, 2026 - 23:44 vuln.today

Analysis Generated

Jun 19, 2026 - 23:44 vuln.today

DescriptionCVE.org

Summary

The logout button does not clear the session. The previous user stays logged in unless another user explicitly logs in.

Details

Not in auto login mode. Hosted on localhost. access_token_lf remains present in both Local Storage and Cookies. refresh_token_lf remains present in Cookies.

Root cause: the /logout endpoint deleted the authentication cookies without matching the original httponly/samesite/secure/domain parameters, so the browser kept them; additionally the frontend did not clear the auth cookies on logout.

LANGFLOW_AUTO_LOGIN: "False"
LANGFLOW_SUPERUSER: <set>
LANGFLOW_SUPERUSER_PASSWORD: <set>
LANGFLOW_SECRET_KEY: <set>
LANGFLOW_NEW_USER_IS_ACTIVE: "False"
LANGFLOW_ENABLE_SUPERUSER_CLI: "False"

PoC

Click Logout. Hit refresh to return to previous screen.

Impact

Users on shared computers may falsely believe they have terminated their session.

Patches

Fixed in 1.7.0 (PRs #10527 and #10528). The logout endpoint now deletes the auth cookies using the same parameters they were created with, and the frontend clears the auth cookies on logout. Upgrade to 1.7.0 or later.

AnalysisAI

Incomplete session termination in Langflow (pip/langflow < 1.7.0) leaves authentication cookies active after logout on shared machines, allowing any subsequent browser user to resume the previous session without credentials. The /logout endpoint issued cookie-deletion calls without matching the httponly, samesite, secure, and domain attributes used at cookie creation, causing browsers to silently ignore the deletion; the frontend compounded this by also failing to clear access_token_lf and refresh_token_lf from storage. No public exploit code has been separately catalogued, though the PoC is trivially reproducible (click Logout, press refresh), and the vulnerability is not listed in CISA KEV.

Technical ContextAI

Langflow is a Python-based visual AI workflow builder (pip package langflow) using a FastAPI backend. Authentication is token-based, with access_token_lf stored in both browser Local Storage and cookies, and refresh_token_lf stored in cookies. The root cause maps directly to CWE-613 (Insufficient Session Expiration): the /logout endpoint in src/backend/base/langflow/api/v1/login.py called response.delete_cookie() with only the cookie name, omitting the original httponly, samesite, secure, and domain attributes. Per HTTP cookie semantics (RFC 6265), a Set-Cookie header with Max-Age=0 only removes a cookie if all scoping attributes match the stored copy exactly; the mismatch meant browsers retained the original cookies. A secondary failure in the React frontend also meant Local Storage entries were not purged. The vulnerability is only present when LANGFLOW_AUTO_LOGIN is set to False, since auto-login mode bypasses token-based cookie authentication entirely.

RemediationAI

Upgrade Langflow to version 1.7.0 or later via pip install --upgrade langflow; the advisory states 1.7.0 as the fix release, though package metadata suggests 1.7.1 - upgrading to the latest available release eliminates ambiguity. The fix is implemented across two PRs: PR #10527 (https://github.com/langflow-ai/langflow/pull/10527) corrects the /logout backend endpoint to pass matching httponly, samesite, secure, and domain parameters when deleting refresh_token_lf, access_token_lf, and apikey_tkn_lflw cookies; PR #10528 (https://github.com/langflow-ai/langflow/pull/10528) adds frontend-side cookie and Local Storage clearing on logout. If an immediate upgrade is not possible, a compensating control for shared-machine deployments is to configure the browser or OS to clear all cookies and storage on window/tab close, or to enforce a session-management policy requiring browser profile isolation per user. Neither workaround is equivalent to the code fix, as neither prevents a second user from accessing a still-open browser tab mid-session.