CVE-2026-53701

An out-of-bounds write vulnerability was found in GStreamer's H.266/VVC PPS picture partition parser in gst-plugins-bad. In the multi-slice-in-tile processing of gst_h266_parser_parse_picture_partition() (gsth266parser.c), the loop iterates without checking that the slice index stays within bounds, writing past three fixed-size arrays (slice_height_in_ctus, slice_top_left_ctu_x, slice_top_left_ctu_y) in the GstH266PPS structure. While the initial proof-of-concept demonstrated a 4-byte out-of-bounds write, the code permits larger writes across multiple iterations. A crafted H.266/VVC media file can trigger this vulnerability.

The H.266/VVC codec parser is part of gst-plugins-bad and is available in GStreamer 1.26 and later. Older versions of GStreamer shipped in Red Hat Enterprise Linux do not include H.266 support and are not affected. The upstream maintainer confirmed the out-of-bounds write is bounded within preallocated structure arrays and did not cause crashes in testing. Practical exploitation for code execution is considered unlikely with modern hardening such as ASLR and stack protectors.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.