A NULL pointer dereference was found in io_file_bitmap_get in io_uring/filetable.c in the io_uring sub-component in the Linux Kernel. When fixed files are unregistered, some context information (file_alloc_{start,end} and alloc_hint) is not cleared. A subsequent request that has auto index selection enabled via IORING_FILE_INDEX_ALLOC can cause a NULL pointer dereference. An unprivileged user can use the flaw to cause a system crash. Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git/commit/?h=io_uring-6.3&?id=761efd55a0227aca3a69deacdaa112fffd44fe37
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s): https://access.redhat.com/security/cve/cve-2023-1583