USN-8526-1: libheif vulnerabilities

Xianrui Dong discovered that libheif had an out-of-bounds read in its
HEIF sequence track parser. An attacker could possibly use this issue
to cause a denial of service or obtain sensitive information. This issue
only affected Ubuntu 26.04 LTS. (CVE-2026-47254)

Junyi Liu discovered that libheif had a null pointer dereference in its
image tiling interface. An attacker could possibly use this issue to
cause a denial of service. (CVE-2026-47709)

Calvin Young and Enoch Chow discovered that libheif had an integer
overflow in its inline mask size calculation. An attacker could
possibly use this issue to cause a denial of service or obtain sensitive
information. (CVE-2026-47714)

Ariel Koren discovered that libheif had an integer underflow in its
grid image tile coordinate transform. An attacker could possibly use
this issue to cause a denial of service or obtain sensitive information.
(CVE-2026-48029)

It was discovered that libheif had a missing bound check in its HEIF
sequence parser, allowing unbounded heap allocation. An attacker could
possibly use this issue to cause a denial of service. (CVE-2026-50142)