CVE-2026-45809
OpenSIPS: Denial of Service in watcherinfo XML generation from oversized watcher URI
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.
INFO
Published Date :
Aug. 5, 2026, 12:17 a.m.
Last Modified :
Aug. 5, 2026, 12:17 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-45809
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update OpenSIPS to version 3.6.6 or later.
- Update OpenSIPS to version 4.0.0-rc1 or later.
- Ensure presence and presence_xml modules are not exposed.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-45809.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-45809 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-45809
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-45809 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-45809 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Aug. 05, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'OpenSIPS', 'product': 'opensips', 'versions': [{'status': 'affected', 'version': '>= 3.4.0, < 3.6.6'}, {'status': 'affected', 'version': '>= 4.0.0-beta, < 4.0.0-rc1'}]}] 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. Added CVSS V4.0 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/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-121 Added Reference https://github.com/OpenSIPS/opensips/commit/c5970d3ee25b457ad2d78fe6e9662a12dae577cd Added Reference https://github.com/OpenSIPS/opensips/commit/dd86461b71ff4a4f5194205896ae5f48f144240d Added Reference https://github.com/OpenSIPS/opensips/security/advisories/GHSA-gx83-2gh8-7v56