{"id":"CVE-2026-74729","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nsoc: aspeed: lpc-snoop: Fix usercopy overflow in snoop_file_read\n\nput_fifo_with_discard() acts as both producer and consumer on the kfifo:\nit calls kfifo_skip() (advanc…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nsoc: aspeed: lpc-snoop: Fix usercopy overflow in snoop_file_read\n\nput_fifo_with_discard() acts as both producer and consumer on the kfifo:\nit calls kfifo_skip() (advanc…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 3772e5da445420543b25825ac2b5971f3743f6e8 < 868c478abce858135db3eb65548a577e4b6747ac","Linux >= 3772e5da445420543b25825ac2b5971f3743f6e8 < 131ab677b03349a5ae48da8722ec7075b37ec66e","Linux >= 3772e5da445420543b25825ac2b5971f3743f6e8 < 1acef6d85bfd98bd9dfe1f08bffa397a4dda8a6f","Linux 4.19"],"published":"2026-08-22","updated":"2026-10-15","sourceUpdated":"2026-10-15T11:17:49.137","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-74729","references":[{"url":"https://git.kernel.org/stable/c/131ab677b03349a5ae48da8722ec7075b37ec66e","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/1acef6d85bfd98bd9dfe1f08bffa397a4dda8a6f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/868c478abce858135db3eb65548a577e4b6747ac","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"epss":0.00198,"epssPercentile":0.0886,"ingestedAt":"2026-10-14T13:30:58.550Z","slug":"CVE-2026-74729","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nsoc: aspeed: lpc-snoop: Fix usercopy overflow in snoop_file_read\n\nput_fifo_with_discard() acts as both producer and consumer on the kfifo:\nit calls kfifo_skip() (advances out) and kfifo_put() (advances in) from\nthe IRQ handler without synchronizing with snoop_file_read(), which also\nconsumes via kfifo_to_user(). On SMP systems this concurrent access can\nleave (in - out) larger than the ring buffer, so __kfifo_to_user()'s clamp\nto (in - out) is ineffective and kfifo_copy_to_user() can attempt a\ncopy_to_user() past the kmalloc-2k backing store:\n\n  usercopy: Kernel memory exposure attempt detected from SLUB object\n  'kmalloc-2k' (offset 0, size 2049)!\n  kernel BUG at mm/usercopy.c!\n  Call trace:\n   usercopy_abort\n   __check_heap_object\n   __check_object_size\n   kfifo_copy_to_user\n   __kfifo_to_user\n   snoop_file_read\n   vfs_read\n\nSerialize kfifo access with a per-channel spinlock shared between the\nIRQ handler (producer) and the file reader (consumer).  Annotate @fifo\nwith __guarded_by(&lock) and opt the driver into context analysis so the\ncompiler enforces that all fifo access holds the lock.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}