UBUNTU-CVE-2026-121942: Medium severity ubuntu/zbar vulnerability

ZBar through 0.23.95 contains an out-of-bounds read vulnerability in zbarsqdecode() in zbar/sqcode.c that allows attackers to read heap memory outside the image buffer via crafted SQ code images. Attackers can supply an image with a skewed SQ code finder pattern near the edge, producing unchecked sample coordinates that crash the decoder and leak bytes into output.