OpenSIPS: Denial of Service in watcherinfo XML generation from oversized watcher URI (CVE-2026-45809) | HOL Guard CVE

High · CVSS 8.7CVE-2026-45809

OpenSIPS: Denial of Service in watcherinfo XML generation from oversized watcher URI

Answer in brief

CVE-2026-45809 records a High severity (CVSS 8.7) vulnerability in OpenSIPS: Denial of Service in watcherinfo XML generation from oversized watcher URI. The current sources do not mark it as known exploited. The current feed maps OpenSIPS/opensips (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 4, 2026Updated Sep 8, 2026Source checked Sep 19, 2026First seen by HOL Aug 4, 2026Material review Sep 8, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 8.7
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Not reported

Why this deserves its current priority

CVSS is 8.7. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps OpenSIPS/opensips (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
OpenSIPS/opensipsgeneric	>= 3.4.0, < 3.6.6 \|\| >= 4.0.0-beta, < 4.0.0-rc1	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for OpenSIPS/opensips.
Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

Published upstream
Aug 4, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 8, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 4, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.