UBUNTU-CVE-2026-89882: High severity ubuntu/linux-hwe-edge vulnerability
In the Linux kernel, the following vulnerability has been resolved: media: rkvdec: hevc: guard INTERREFPICSETPRED index underflow strefpicsetprediction() computes the reference RPS index as strpsidx - (deltaidxminus1 + 1) per HEVC spec equation 7-59. Both operands are u8, so when deltaidxminus1 + 1 exceeds the current index the subtraction wraps and the subsequent array access at calculatedrpsstsets[refrpsidx] reads far out of bounds. A userspace V4L2 client that can open the RKVDEC m2m decoder can submit an EXTSPSSTRPS control with INTERREFPICSETPRED set and deltaidxminus1 crafted to trigger the underflow. Reject the entry early when the reference index would underflow.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Compensating control
In the RKVDEC HEVC decoder's st_ref_pic_set_prediction() handling, reject an EXT_SPS_ST_RPS entry early when st_rps_idx - (delta_idx_minus1 + 1) would underflow, preventing an out-of-bounds access to calculated_rps_st_sets[ref_rps_idx].