CVE-2026-45809

CVE-2026-45809 · OpenSIPS: Denial of Service in watcherinfo XML generation from oversized watcher URI

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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.

CVSS 8.7 · High · EPSS 0.6%

Published

2026-08-04T23:30:03.111Z

Updated

2026-08-05T13:57:39.468Z

Stack: system

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