{"id":"DEBIAN-CVE-2024-56612","details":"In the Linux kernel, the following vulnerability has been resolved:  mm/gup: handle NULL pages in unpin_user_pages()  The recent addition of \"pofs\" (pages or folios) handling to gup has a flaw: it assumes that unpin_user_pages() handles NULL pages in the pages** array.  That's not the case, as I discovered when I ran on a new configuration on my test machine.  Fix this by skipping NULL pages in unpin_user_pages(), just like unpin_folios() already does.  Details: when booting on x86 with \"numa=fake=2 movablecore=4G\" on Linux 6.12, and running this:      tools/testing/selftests/mm/gup_longterm  ...I get the following crash:  BUG: kernel NULL pointer dereference, address: 0000000000000008 RIP: 0010:sanity_check_pinned_pages+0x3a/0x2d0 ... Call Trace:  \u003cTASK\u003e  ? __die_body+0x66/0xb0  ? page_fault_oops+0x30c/0x3b0  ? do_user_addr_fault+0x6c3/0x720  ? irqentry_enter+0x34/0x60  ? exc_page_fault+0x68/0x100  ? asm_exc_page_fault+0x22/0x30  ? sanity_check_pinned_pages+0x3a/0x2d0  unpin_user_pages+0x24/0xe0  check_and_migrate_movable_pages_or_folios+0x455/0x4b0  __gup_longterm_locked+0x3bf/0x820  ? mmap_read_lock_killable+0x12/0x50  ? __pfx_mmap_read_lock_killable+0x10/0x10  pin_user_pages+0x66/0xa0  gup_test_ioctl+0x358/0xb20  __se_sys_ioctl+0x6b/0xc0  do_syscall_64+0x7b/0x150  entry_SYSCALL_64_after_hwframe+0x76/0x7e","modified":"2026-09-15T09:03:19.946102676Z","published":"2024-12-27T15:15:20.687Z","upstream":["CVE-2024-56612"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2024-56612"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:13","purl":"pkg:deb/debian/linux?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.12.5-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2024-56612.json"}},{"package":{"name":"linux","ecosystem":"Debian:14","purl":"pkg:deb/debian/linux?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.12.5-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2024-56612.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}