CVE-2026-28799: PJSIP: Heap use-after-free in PJSIP presence subscription termination handler

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-03-06 · updated 2026-06-17
Weakness: CWE-416

Description

PJSIP is a free and open source multimedia communication library written in C. Prior to version 2.17, a heap use-after-free vulnerability exists in PJSIP's event subscription framework (evsub.c) that is triggered during presence unsubscription (SUBSCRIBE with Expires=0). This issue has been patched in version 2.17.

Affected products

Pjsip: before 2.17 — fixed in 2.17

How to fix

Upgrade to a fixed version: Pjsip 2.17. Check the vendor advisory for mitigations.

References

https://github.com/pjsip/pjproject/commit/e06ff6c64741cc1675fd3296615910f532f6b1a1
https://github.com/pjsip/pjproject/security/advisories/GHSA-8fj4-fv9f-hjpc

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