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.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
OpenSIPS opensips affected
Version Status Constraints
>= 3.4.0, < 3.6.6 affected —
>= 4.0.0-beta, < 4.0.0-rc1 affected —

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Advisories

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Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/OpenSIPS/opensips/commit/c5970d3ee25b457ad2d78fe6e9662a12dae577cd cve-icon
https://github.com/OpenSIPS/opensips/commit/dd86461b71ff4a4f5194205896ae5f48f144240d cve-icon
https://github.com/OpenSIPS/opensips/security/advisories/GHSA-gx83-2gh8-7v56 cve-icon
History

Wed, 05 Aug 2026 01:30:00 +0000

Type Values Removed Values Added
First Time appeared Opensips
Opensips opensips
Vendors & Products Opensips
Opensips opensips

Tue, 04 Aug 2026 23:45:00 +0000

Type Values Removed Values Added
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.
Title OpenSIPS: Denial of Service in watcherinfo XML generation from oversized watcher URI
Weaknesses CWE-121
References
Metrics cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-08-04T23:30:03.111Z

Reserved: 2026-05-13T08:19:32.604Z

Link: CVE-2026-45809

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-05T01:15:03Z

Weaknesses