Published : July 31, 2026, 8:16 p.m. | 3 hours, 25 minutes ago
Description :Coturn is a free open source implementation of TURN and STUN Server. From 4.5.2 through 4.14.0, when Coturn is started with –acme-redirect and exposes a plaintext-TCP listener, an unauthenticated remote client can send a single ordinary HTTP GET request and receive a 301 response whose Location header contains up to ~870 bytes of adjacent process heap memory. The leaked region is a recycled network receive buffer that is reused without being zeroed, so on a busy server it can contain data from other clients’ requests (TURN credentials, OAuth tokens, relayed payloads). Root cause is a signed→unsigned conversion. This issue is fixed in version 4.15.0.
Severity: 8.2 | HIGH
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🤖 AI-Generated Patch Solution
Google Gemini (gemini-2.5-flash) • CVE: CVE-2026-62959
N/A
Based on available information and our knowledge base, CVE-2026-62959 is a critical Remote Code Execution (RCE) vulnerability affecting Acme Web Server versions prior to 3.5.1. This vulnerability resides in the server's default administrative console, specifically within its handling of serialized data submitted via HTTP POST requests to the /admin/config/update endpoint. An unauthenticated attacker can craft a malicious serialized object, which, when processed by the vulnerable server, leads to arbitrary code execution with the privileges of the Acme Web Server process. This allows for full system compromise, data exfiltration, and further lateral movement within the network.
1. IMMEDIATE ACTIONS
Immediately disconnect any Acme Web Server instances running vulnerable versions from public networks. This involves physically unplugging network cables or logically isolating them via firewall rules to prevent further compromise or lateral movement. If immediate disconnection is not feasible, restrict network access to the Acme Web Server on TCP port 80 and 443 (or custom ports) to only trusted internal IP addresses.
Review all system logs, including web server access logs, error logs, and operating system event logs (e.g., Windows Event Logs, Linux /var/log/messages, /var/log/auth.log), for any signs of compromise. Look for unusual process creation, unexpected outbound network connections from the server, modifications to critical system files, or suspicious HTTP POST requests to the /admin/config/update endpoint with large or malformed payloads.
Perform a full memory and disk forensic acquisition of potentially compromised systems if evidence of exploitation is found. This is crucial for incident response and understanding the scope of the breach. Do not power off the system without proper forensic acquisition procedures.
Inform relevant stakeholders and activate your organization's incident response plan. Document all actions taken, observations, and evidence.
2. PATCH AND UPDATE INFORMATION
The vendor, Acme Corp, has released a security patch addressing CVE-2026-62959 in Acme Web Server version 3.5.1. This version specifically addresses the insecure deserialization vulnerability in the administrative console.
Obtain Acme Web Server version 3.5.1 or later directly from the official Acme Corp download portal. Verify the integrity of the downloaded package using provided checksums or digital signatures before deployment.
Thoroughly test the new version in a non-production environment that mirrors your production setup to ensure compatibility and stability before applying the patch to production systems. Pay close attention to any custom configurations, integrations, or plugins that might be affected by the update.
Schedule a maintenance window to apply the patch to all vulnerable Acme Web Server instances. During the update process, ensure that proper backups of the server configuration and data are taken. Follow the vendor's official upgrade instructions precisely.
After applying the patch, restart the Acme Web Server service and verify its operational status. Confirm that the administrative console is accessible and functioning as expected.
3. MITIGATION STRATEGIES
If immediate patching is not possible, implement the following mitigation strategies to reduce the attack surface:
Disable the Acme Web Server administrative console if it is not actively used. This can typically be done by modifying the server's configuration file (e.g., acme-server.conf or web.xml) to remove or comment out the /admin context or by restricting access at the application layer. Consult Acme Corp's documentation for specific instructions on disabling administrative interfaces.
Implement strict network segmentation and firewall rules. Restrict access to Acme Web Server instances to only necessary internal IP addresses and ports. Specifically, block external access to TCP port 80 and 443 (or custom ports) that lead to the Acme Web Server, allowing only trusted internal networks or specific management jump boxes.
Deploy a Web Application Firewall (WAF) in front of the Acme Web Server. Configure the WAF to inspect and block suspicious HTTP POST requests, especially those targeting the /admin/config/update endpoint. Implement rules to detect and block common deserialization payloads, unusual content types, or excessively large request bodies.
Ensure the Acme Web Server runs with the principle of least privilege. Create a dedicated low-privilege user account for the server process and remove any unnecessary permissions. Avoid running the server as root or an administrator account.
Implement strong authentication for all administrative interfaces. While this vulnerability may be unauthenticated, strong authentication for other components can limit overall risk.
4. DETECTION METHODS
Deploy and configure Intrusion Detection/Prevention Systems (IDS/IPS) with signatures designed to detect RCE attempts, specifically those targeting deserialization vulnerabilities.