OpenSIPS up to 3.6.5 Presence handle_publish denial of service

Summaryinfo

A vulnerability marked as problematic has been reported in OpenSIPS up to 3.6.5. This impacts the function handle_publish of the component Presence Module. Performing a manipulation results in denial of service. This vulnerability is reported as CVE-2026-45084. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability, which was classified as problematic, was found in OpenSIPS up to 3.6.5. This affects the function handle_publish of the component Presence Module. The manipulation with an unknown input leads to a denial of service vulnerability. CWE is classifying the issue as CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. This is going to have an impact on availability. The summary by CVE is:

OpenSIPS is a Session Initiation Protocol (SIP) server implementation. Versions 3.4.0 through 3.6.5 contain a denial of service vulnerability in the presence module. When the presence module's handle_publish() function processes a SIP PUBLISH request with an Event: presence header and a message body while the configuration option enable_sphere_check=1 is set, it invokes the get_content_type() macro without first calling parse_content_type_hdr(), causing it to dereference uninitialized or NULL Content-Type parsing state and crash. If a Content-Type header is present but unparsed, msg->content_type->parsed is NULL and is dereferenced as a content_t pointer; if the request lacks a Content-Type header entirely, msg->content_type itself is NULL, and both cases lead to a crash. A remote attacker can therefore cause a denial of service against an affected instance with a single PUBLISH request over UDP or TCP, using either a valid Content-Type: application/pidf+xml request or one with the header removed, and the vulnerable code path itself does not enforce authentication (though a deployment's routing configuration may require it before this route is reached). The issue has been fixed in version 3.6.6 and 4.0.0-rc1.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-45084 since 05/08/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1499 for this issue.

Upgrading to version 3.6.6 or 4.0.0-rc1 eliminates this vulnerability.

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Productinfo

Name

• OpenSIPS

Version

• 3.6.0
• 3.6.1
• 3.6.2
• 3.6.3
• 3.6.4
• 3.6.5

Website

• Product: https://github.com/OpenSIPS/opensips/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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