Out-of-bounds Read in Zlmediakit

CVE-2026-35203

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.

Vulnerability class: Buffer Overflow

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.005 (41.8th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 42nd percentile — 41.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-35203: held from 0.003 to 0.005.

EPSS over last 30 days · oldest: 0.003 · newest: 0.005 · change: +0.002

Affected products

  • Zlmediakit — versions < 435dcbcbbf700fd63b2ca9eac6cef3b5ea75169d

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-35203?
CVE-2026-35203 is a high-severity vulnerability in Zlmediakit, classified under Out-of-bounds Read. CVSS score: 7.5/10. Published 2026-04-06.
How severe is CVE-2026-35203?
High severity. CVSS v3 base score is 7.5 out of 10.