Bug 2511527

Summary:	CVE-2026-45809 opensips: denial of service in watcherinfo XML generation from oversized watcher URI [fedora-all]
Product:	[Fedora] Fedora	Reporter:	Guilherme de Almeida Suckevicz <gsuckevi>
Component:	opensips	Assignee:	Peter Lemenkov <lemenkov>
Status:	CLOSED CURRENTRELEASE	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	high	Docs Contact:
Priority:	high
Version:	rawhide	CC:	lemenkov
Target Milestone:	---	Keywords:	Security, SecurityTracking
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:	{"flaws": ["4b3b0501-aa53-401c-ac11-6b81961d59fd"]}
Fixed In Version:	opensips-3.6.7-1.fc43 opensips-3.6.7-1.fc44 opensips-4.0.0-9.fc45	Doc Type:	---
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2026-08-05 13:42:37 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	2511294

Description Guilherme de Almeida Suckevicz 2026-08-05 13:34:11 UTC

Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

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.

Comment 1 Peter Lemenkov 2026-08-05 13:42:37 UTC

OpenSIPS in Fedora is not affected — every active branch already carries the fix:

- rawhide/f45: opensips-4.0.0-9.fc45
- f44: opensips-3.6.7-1.fc44 (built 2026-06-24)
- f43: opensips-3.6.7-1.fc43 (built 2026-06-24)

There are no EPEL branches for this package, so the above is the full scope of [fedora-all].

Verified against upstream git rather than the advisory version claims. The fix is c5970d3ee ("presence: fix winfo XML overflow on long URIs"), which drops the fixed 200-byte stack buffer in modules/presence/notify.c and builds the watcher node with xmlNodeSetContentLen() using the URI's actual length instead of strncpy() into that buffer. git tag --contains places it in 3.6.6 and 3.6.7.

For 4.0.0 the fix was confirmed by content — modules/presence/notify.c at tag 4.0.0 uses xmlNodeSetContentLen() and no longer declares the char content[200] buffer.

Closing CURRENTRELEASE.