Vulnerability 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.
Related Weaknesses (CWE)
References
- https://github.com/OpenSIPS/opensips/commit/c5970d3ee25b457ad2d78fe6e9662a12dae5
- https://github.com/OpenSIPS/opensips/commit/dd86461b71ff4a4f5194205896ae5f48f144
- https://github.com/OpenSIPS/opensips/security/advisories/GHSA-gx83-2gh8-7v56
- https://github.com/OpenSIPS/opensips/security/advisories/GHSA-gx83-2gh8-7v56
FAQ
What is CVE-2026-45809?
CVE-2026-45809 is a documented vulnerability. 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 a...
How severe is CVE-2026-45809?
CVSS scoring is not yet available for CVE-2026-45809. Check NVD for updates.
Is there a patch for CVE-2026-45809?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.