Unraid OS 6.8.0 Authentication Bypass and Remote Code Execution Vulnerability (CVE-2020-5849) Security Advisory
Executive & SecOps Summary
SECOPS ASSESSMENTUnraid OS version 6.8.0
Remote attackers can bypass authentication to gain administrative access and execute arbitrary code with root privileges on the target system.
Immediately upgrade Unraid OS to the latest stable version (6.8.1 or higher) and restrict external access to the management interface.
Affected Products & Version Scope
Remediation & Live Workaround Commands
PATCH & WORKAROUND1. Official Patch & Version Upgrade Commands
Users running Unraid OS 6.8.0 must immediately upgrade to version 6.8.1 or higher via 'Tools' -> 'Update OS' in the Web GUI. If the GUI is inaccessible, perform a manual update by replacing the boot files on the USB drive.
# Check the current Unraid version via SSH
cat /etc/unraid-version
# Download and extract the stable update package (e.g., 6.8.2)
wget https://unraid-dl.sfo2.cdn.digitaloceanspaces.com/stable/unraid-6.8.2-x86_64.zip
unzip unraid-6.8.2-x86_64.zip -d /boot/
reboot2. Temporary Workaround & Hardening Configuration
If an immediate upgrade is not feasible, restrict access to the Unraid management interface using a reverse proxy or firewall rules to block external traffic.
# Nginx reverse proxy configuration to restrict access to trusted IPs
server {
listen 443 ssl;
server_name unraid.local;
# Allow only trusted internal networks
allow 192.168.1.0/24;
deny all;
location / {
proxy_pass http://127.0.0.1:80;
proxy_set_header Host $host;
}
}3. Log Audit & IoC Verification Commands
Inspect the system and web server logs for unauthorized session creation or suspicious authentication bypass attempts.
# Search syslog for abnormal authentication or session activities
grep -i 'auth' /var/log/syslog | grep -E 'invalid|bypass|session'
# Verify the running emhttpd process and listening ports
netstat -tulpn | grep emhttpdBlock Kernel Privilege Escalation & Ransomware Payloads Before You Can Reboot
Protect unpatched Windows, Linux, and macOS workloads against in-memory exploitation and lateral movement with autonomous EDR.
Technical Root Cause & Exploitation Mechanics
1. Vulnerability Overview & Root Cause
This vulnerability (CVE-2020-5849) is a critical authentication bypass vulnerability in the web management interface of Unraid OS version 6.8.0. The root cause lies in loose comparison or improper string validation (CWE-697) within the authentication logic of the web server. This allows an unauthenticated attacker to craft a request that bypasses session validation checks entirely.
2. Exploitation Mechanics & Attack Scenario
An attacker sends a specially crafted HTTP request to the Unraid management utility (emhttpd). Due to flawed comparison logic in the authentication handler, the application incorrectly validates empty or manipulated session tokens as authorized. Once authenticated, the attacker gains administrative access to the web panel, which can be chained with other vulnerabilities (such as CVE-2020-5847) to execute arbitrary OS commands as the root user.
3. Infrastructure & Business Impact
Unraid is widely deployed as a Network Attached Storage (NAS) and application server. This vulnerability is highly critical, as evidenced by its inclusion in the CISA KEV catalog and an EPSS score exceeding 0.93. Successful exploitation allows complete system compromise, leading to data exfiltration, ransomware deployment, or lateral movement within the internal network.
Official Vendor Advisories & References
Unraid 6.8.0 allows authentication bypass.
Frequently Asked SecOps Questions (CVE-2020-5849)
FAQQ1. How critical is CVE-2020-5849 and is it actively exploited in the wild?
CVE-2020-5849 is rated CVSS 7.5 (HIGH) with a 30-day EPSS exploitation probability of 93.2%. It is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, requiring immediate emergency remediation.
Q2. Which vendors and products are affected by CVE-2020-5849?
Primary impacted vendors include lime technology across unraid. Scope summary: Unraid OS version 6.8.0 (Other versions and 6.8.1+ are not affected)
Q3. What temporary mitigations or workarounds exist for CVE-2020-5849 before patching?
[Mitigation] Immediately upgrade Unraid OS to the latest stable version (6.8.1 or higher) and restrict external access to the management interface. Follow the CLI remediation commands and interactive SecOps checklist on this page to restrict exposure prior to your maintenance window.
Generate an Internal Engineering Notice or CISO Report for CVE-2020-5849
Instantly format this advisory into an executive CISO summary or engineering patch ticket.
🔗 Related Advisories in Similar Stack (lime technology)
View Category →Apple macOS Screen Sharing Authentication Bypass Vulnerability (CVE-2026-65400)
[Affected Scope] macOS systems running versions prior to Sequoia 15.7.9, Sonoma 14.8.9, Tahoe 26.6.1/26.7, or Golden Gate 27 with Screen Sharing or VNC services enabled
DAEMON Tools Lite Official Installer Supply Chain Attack and Trojanized Binaries (CVE-2026-8398)
[Affected Scope] DAEMON Tools Lite Windows versions 12.5.0.2421 through 12.5.0.2434 distributed between April 8, 2026, and May 5, 2026
Microsoft Windows Shell Command Injection and Security Feature Bypass (CVE-2026-96951) Advisory
[Affected Scope] All supported versions of Windows OS including Windows 10, 11, and Windows Server.
Apple iOS and macOS Out-of-bounds Write Remote Code Execution Vulnerability (CVE-2026-86950) Security Advisory
[Affected Scope] All Apple devices running versions prior to iOS 18.7.11/26.7.1 and macOS Sequoia 15.8.1/Tahoe 26.7.1.
Subscribe to Daily Vulnerability Briefings & KEV Alerts
Concise morning briefings for SecOps, DevSecOps, and SRE teams covering newly exploited CVEs and mitigation priorities.