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5.1
PJSIP H.264 Packetizer Heap Buffer Underflow
CVE-2026-26203
Summary
Versions of PJSIP prior to 2.17 are at risk of a serious memory error that could allow an attacker to access sensitive data or disrupt a system. This issue is fixed in version 2.17, which is recommended for all affected users. Update to the latest version of PJSIP to protect against this risk.
What to do
No fix is available yet. Check with your software vendor for updates.
Affected software
| Vendor | Product | Affected versions | Fix available |
|---|---|---|---|
| pjsip | pjsip | <= 2.17 | – |
Original title
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 process...
Original description
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.
nvd CVSS3.1
6.5
nvd CVSS4.0
5.1
Vulnerability type
CWE-416
Use After Free
Published: 19 Feb 2026 · Updated: 11 Mar 2026 · First seen: 6 Mar 2026