PJSIP is a free and open source multimedia communication library. Versions prior to 2.17 have a critical heap buffer underflow vulnerability in PJSIP's H.264 packetizer. The bug occurs when processing malformed H.264 bitstreams without NAL unit start codes, where the packetizer performs unchecked pointer arithmetic that can read from memory located before the allocated buffer. Version 2.17 contains a patch for the issue.
https://github.com/pjsip/pjproject/security/advisories/GHSA-p965-mf7j-gwv8
https://github.com/pjsip/pjproject/commit/5aee54f09d4f91538d55279d7316591b28fded6c
Published: 2026-02-19
Updated: 2026-02-20
Base Score: 4.6
Vector: CVSS2#AV:L/AC:L/Au:S/C:N/I:N/A:C
Severity: Medium
Base Score: 6.5
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
Severity: Medium
Base Score: 5.1
Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:L
Severity: Medium
EPSS: 0.00014