CVE intelligence and bounded remediation

CVE-2024-56612 — Linux Linux Kernel security vulnerability

Medium CVSS 5.5

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: <TASK> ? __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+0x…

Severity
Medium
CVSS
5.5 (3.1)
Published
2024-12-27
CISA KEV
Not currently listed
Ecosystem
linux/kernel
Weaknesses
CWE-476

Affected products

  • linux / linux_kernel
  • linux / linux_kernel / 6.13

Matched remediation archetype

Buffer bounds, memory safety, and memory corruption

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Check exposure

  • Identify affected native-code versions, build flags, architectures, parsers, codecs, drivers, and input paths in all shipped artifacts.
  • Determine whether untrusted data reaches the affected routine and the process privilege, sandbox, and network exposure.
  • Confirm statically linked, vendored, firmware, and platform-provided copies, not only package-manager records.

Remediate safely

  • Apply the maintained upstream correction or replace the affected component, then rebuild every dependent artifact from clean inputs.
  • Adopt bounds-checked interfaces, validated sizes and integer conversions, clear ownership, and memory-safe components where practical.
  • Enable supported compiler and runtime hardening and add sanitized tests and fuzz regression seeds derived from non-weaponized fixtures.

Authoritative sources

Complete CVE record and remediation plan

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