In the Linux kernel, the following vulnerability has been resolved: squashfs: harden sanity check in squashfs_read_xattr_id_table While mounting a corrupted filesystem, a signed integer '*xattr_ids' can become less than zero. This leads to the incorrect computation of 'len' and 'indexes' values which can cause null-ptr-deref in copy_bio_to_actor() or out-of-bounds accesses in the next sanity checks inside squashfs_read_xattr_id_table(). Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
The product dereferences a pointer that it expects to be valid but is NULL.