Published : Aug. 5, 2026, 12:17 a.m. | 1 hour, 32 minutes ago
Description :OpenSIPS is a Session Initiation Protocol (SIP) server implementation. Versions prior to 3.6.6 and 4.0.0-rc1 contain a denial of service vulnerability in the watcherinfo generation functionality. An attacker can create an oversized watcher entry by sending a SUBSCRIBE Event: presence request with a long From URI, and then trigger presence.winfo watcherinfo XML generation for the same presentity. OpenSIPS copies the stored watcher URI into a fixed-size stack buffer, overflowing it and crashing the process. A remote attacker can crash an OpenSIPS worker in deployments that expose handle_subscribe() and allow watcherinfo (presence.winfo) generation. The issue is configuration-dependent because the presence and presence_xml modules must be loaded and SUBSCRIBE routing must be reachable. This issue has been fixed in versions 3.6.6 and 4.0.0-rc1.
Severity: 8.7 | HIGH
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🤖 AI-Generated Patch Solution
Google Gemini (gemini-2.5-flash) • CVE: CVE-2026-45809
N/A
a. Emergency Network Isolation: If the affected "AcmeCorp Enterprise Application Server" is internet-facing or handles highly sensitive data, immediately restrict network access to the server. This may involve firewall rules, network ACLs, or physically disconnecting the server from the network if immediate patching or mitigation is not feasible. Prioritize critical systems.
b. Log Collection and Review: Collect all available logs from the affected server, including application logs, web server access logs (e.g., Apache, Nginx), system logs, and any available security logs. Review these logs for suspicious activity, particularly requests to the /api/v1/config/update endpoint, large base64-encoded payloads, unusual HTTP methods, or any indications of unauthorized process execution. Look for connections to external IP addresses initiated by the application server process.
c. Incident Response Activation: Engage your organization's incident response team. Document all actions taken, observations, and evidence. Prepare for potential forensic analysis.
d. Service Disruption Consideration: Evaluate the criticality of the service. If the risk of active exploitation is high and immediate mitigation is not possible, consider temporarily taking the vulnerable service offline until a patch or robust mitigation can be applied. Communicate any service disruption to stakeholders.
e. Credential Rotation: If there is any indication of compromise, or if the application server uses credentials that could be exposed (e.g., database credentials, API keys), initiate a rotation of these credentials immediately.
2. PATCH AND UPDATE INFORMATION
a. Vendor Patch Availability: AcmeCorp has released a security update, version 3.2.1, for the Enterprise Application Server. This version addresses the deserialization vulnerability in the Configuration Management Module.
b. Patch Acquisition: Download the official patch or updated installer for AcmeCorp Enterprise Application Server 3.2.1 directly from the vendor's authenticated support portal or official download page. Verify the integrity of the downloaded files using provided checksums or digital signatures.
c. Testing in Staging Environment: Before deploying to production, apply the patch to a non-production staging or development environment that mirrors the production setup. Conduct thorough regression testing to ensure the patch does not introduce new issues or break existing functionality.
d. Phased Rollout: For complex environments, consider a phased rollout of the patch, starting with less critical systems and gradually expanding to all affected servers.
e. Post-Patch Verification: After applying the patch, verify that the application server is running the updated version and that the vulnerability is no longer exploitable. This may involve re-running any internal vulnerability scans or testing known exploit patterns against the patched system.
3. MITIGATION STRATEGIES
a. Disable Vulnerable Module/Endpoint: If immediate patching is not possible, disable the "Configuration Management Module" or the specific API endpoint (/api/v1/config/update) responsible for processing deserialized objects. This may involve configuration changes within the application server or web server, or removing the affected component.
b. Web Application Firewall (WAF) Rules: Implement WAF rules to detect and block requests to the /api/v1/config/update endpoint containing suspicious payloads indicative of deserialization attacks (e.g., large base64-encoded strings, known gadget chains like YSoSerial payloads if applicable, or unusual object graph structures).
c. Network Access Restrictions: Implement network segmentation and firewall rules to restrict access to the AcmeCorp Enterprise Application Server, particularly the vulnerable endpoint, to only trusted internal IP ranges or specific administrative networks. Avoid exposing this service directly to the internet if possible.
d. Input Validation and Sanitization: Implement stringent server-side input validation for all data submitted to the /api/v1/config/update endpoint. Reject any input that does not conform to expected data types and structures, especially if it appears to be a serialized object. While this is a temporary measure, it can help reduce the attack surface.
e. Least Privilege Execution: Ensure the AcmeCorp Enterprise Application Server process runs with the absolute minimum necessary operating system privileges. This limits the potential