CVE-2026-89778 isofs: fix out-of-bounds page array access on empty zisofs block

In the Linux kernel, the following vulnerability has been resolved: isofs: fix out-of-bounds page array access on empty zisofs block zisofsuncompressblock's empty-block fast path returns pcount 17, so a crafted "ZF" Rock Ridge record can set it below PAGESHIFT; the bug is reached by an ordinary...

CVE-2026-89778

CVE-2026-89778 is an out-of-bounds page array access in the Linux kernel's zisofs (compressed ISO9660) filesystem. The root cause is in zisofs_uncompress_block()'s empty-block fast path, which returns pcount <