CVE-2026-14950: Session Expiration Auth Bypass Vulnerability

CVE-2026-14950 Overview

CVE-2026-14950 is an insufficient session expiration vulnerability [CWE-613] affecting the FDS web interface. An unauthenticated remote attacker in possession of a valid session identifier can continue using the session after it should have expired. The flaw increases the risk associated with stolen, leaked, shared, or unattended sessions and enables unauthorized continued access to the web interface. The vulnerability was disclosed through a CERT-VDE security advisory and carries network-based exploitability with high impact to confidentiality, integrity, and availability.

Critical Impact
Attackers holding a captured session identifier can maintain persistent access to the FDS web interface beyond expected session lifetimes, bypassing session-based access controls.

Affected Products

FDS web interface (see CERT-VDE Security Advisory for specific affected versions)

Discovery Timeline

2026-08-20 - CVE-2026-14950 published to NVD
2026-08-20 - Last updated in NVD database

Technical Details for CVE-2026-14950

Vulnerability Analysis

The vulnerability stems from insufficient enforcement of session expiration on the FDS web interface. Session identifiers that should have been invalidated remain valid on the server side after their intended lifetime. This allows any party holding a captured session token to continue authenticated actions without re-authentication.

Because the flaw is exploitable over the network without prior authentication, an attacker who obtains a session identifier through phishing, network interception, log exposure, browser artifacts, or shared workstations can act as the original user. The CWE-613 classification confirms the root issue lies in session management logic rather than credential handling.

Root Cause

The root cause is improper session timeout enforcement in the FDS web interface session management module. The server fails to invalidate session tokens after the expected expiration window elapses. The application continues to accept expired session identifiers as valid credentials for subsequent requests.

Attack Vector

The attack vector is network-based and requires no user interaction on the target system. An attacker must first obtain a valid session identifier through means such as network sniffing on unencrypted channels, session token leakage in logs or referrers, or physical access to unattended sessions. The attacker then replays the identifier in HTTP requests to the FDS web interface to gain continued authenticated access.

Refer to the CERT-VDE Security Advisory for vendor-specific exploitation details.

Detection Methods for CVE-2026-14950

Indicators of Compromise

Authenticated sessions active well beyond configured or expected session timeout windows.
Repeated use of the same session identifier from multiple source IP addresses or user-agent strings.
Access to FDS web interface functions outside normal working hours by accounts with predictable schedules.

Detection Strategies

Correlate authentication events with session activity to identify sessions that persist past expected lifetimes.
Alert on session identifiers reused after long periods of inactivity or from geolocations inconsistent with the original login.
Monitor HTTP access logs on the FDS web interface for anomalous session token reuse patterns.

Monitoring Recommendations

Ingest FDS web interface access logs into a centralized logging platform for retention and correlation.
Baseline normal session durations per user role and alert on deviations.
Track session token issuance and last-use timestamps to identify tokens exceeding policy thresholds.

How to Mitigate CVE-2026-14950

Immediate Actions Required

Review the CERT-VDE Security Advisory VDE-2026-078 for vendor-supplied fixed versions and apply them.
Force logout of all active FDS web interface sessions and require users to re-authenticate.
Restrict network access to the FDS web interface to trusted management networks only.

Patch Information

Consult the CERT-VDE Security Advisory for the vendor-supplied patched firmware or software versions and remediation guidance. Apply the vendor patch as the primary remediation.

Workarounds

Place the FDS web interface behind a reverse proxy or VPN that enforces its own session timeout policy.
Reduce administrator session lifetimes and require re-authentication for privileged operations.
Enforce TLS on all FDS web interface traffic to reduce the risk of session identifier interception.
Instruct users to explicitly log out and avoid leaving browser sessions unattended on shared workstations.

bash

# Example: restrict FDS web interface access to a management subnet using iptables
iptables -A INPUT -p tcp --dport 443 -s 10.10.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP