Out-of-bounds Read in Gstreamer

CVE-2026-12892

A flaw was found in GStreamer's gst-plugins-bad package. When processing a specially crafted H.264 video file containing malformed MVC or SVC extension slice NAL units, a 1-byte heap out-of-bounds read can occur during parsing. This happens when the parser attempts to check slice boundary information without first verifying that the NAL unit contains enough data beyond the extension header. An attacker could exploit this by tricking a user into opening a malicious H.264 video file, potentially causing the application to crash or leak a single byte of heap memory.

Vulnerability class: Buffer Overflow

EPSS: 0.001 (1.9th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.4 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-12892?
CVE-2026-12892 is a medium-severity vulnerability in Gstreamer, classified under Out-of-bounds Read. CVSS score: 4.4/10. Published 2026-06-23.
How severe is CVE-2026-12892?
Medium severity. CVSS v3 base score is 4.4 out of 10.