CVE-2026-45809
Versions prior to 3.6.6 and 4.0.0-rc1 contain a denial of service vulnerability in the watcherinfo generation functionality.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.39%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 4.0
- 8.7 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.39% probability · 32th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-121
- Source
- security-advisories@github.com
References
- https://github.com/OpenSIPS/opensips/commit/c5970d3ee25b457ad2d78fe6e9662a12dae577cd
- https://github.com/OpenSIPS/opensips/commit/dd86461b71ff4a4f5194205896ae5f48f144240d
- https://github.com/OpenSIPS/opensips/security/advisories/GHSA-gx83-2gh8-7v56
- https://github.com/OpenSIPS/opensips/security/advisories/GHSA-gx83-2gh8-7v56
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.