This vulnerability in GStreamer's gst-plugins-bad package allows an attacker to cause a 1-byte heap out-of-bounds read when parsing malformed MVC or SVC extension slice NAL units in H.264 video files. The flaw arises from insufficient validation of NAL unit data length before accessing slice boundary information. An attacker can exploit this by convincing a user to open a crafted H.264 video file, leading to potential application crash or minor information leakage. The issue affects Red Hat Enterprise Linux 10, but no specific affected versions or patches are detailed in the advisory. The CVSS 3.1 base score is 4.4, reflecting low complexity and limited impact.

Successful exploitation can cause an application crash (availability impact) or leak a single byte of heap memory (confidentiality impact). The impact is limited due to the small amount of leaked data and the requirement for user interaction. There is no indication of privilege escalation or integrity impact. No known exploits are reported in the wild.

Patch status is not yet confirmed — check the Red Hat advisory at https://access.redhat.com/security/cve/CVE-2026-12892 for current remediation guidance. Until a patch is available, users should avoid opening untrusted or suspicious H.264 video files containing MVC or SVC extensions. No official fix or temporary workaround is currently documented.