Linux Kernel up to 7.1.8 lpc-snoop mm/usercopy.c snoop_file_read heap-based overflow

Summaryinfo

A vulnerability has been found in Linux Kernel up to 7.1.8 and classified as very critical. This issue affects the function snoop_file_read of the file mm/usercopy.c of the component lpc-snoop. This manipulation causes heap-based overflow. This vulnerability appears as CVE-2026-74729. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability classified as very critical was found in Linux Kernel up to 7.1.8. Affected by this vulnerability is the function snoop_file_read of the file mm/usercopy.c of the component lpc-snoop. The manipulation with an unknown input leads to a heap-based overflow vulnerability. The CWE definition for the vulnerability is CWE-122. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: soc: aspeed: lpc-snoop: Fix usercopy overflow in snoop_file_read put_fifo_with_discard() acts as both producer and consumer on the kfifo: it calls kfifo_skip() (advances out) and kfifo_put() (advances in) from the IRQ handler without synchronizing with snoop_file_read(), which also consumes via kfifo_to_user(). On SMP systems this concurrent access can leave (in - out) larger than the ring buffer, so __kfifo_to_user()'s clamp to (in - out) is ineffective and kfifo_copy_to_user() can attempt a copy_to_user() past the kmalloc-2k backing store: usercopy: Kernel memory exposure attempt detected from SLUB object 'kmalloc-2k' (offset 0, size 2049)! kernel BUG at mm/usercopy.c! Call trace: usercopy_abort __check_heap_object __check_object_size kfifo_copy_to_user __kfifo_to_user snoop_file_read vfs_read Serialize kfifo access with a per-channel spinlock shared between the IRQ handler (producer) and the file reader (consumer). Annotate @fifo with __guarded_by(&lock) and opt the driver into context analysis so the compiler enforces that all fifo access holds the lock.

The advisory is shared at git.kernel.org. This vulnerability is known as CVE-2026-74729 since 08/15/2026. The exploitation appears to be easy. The attack can be launched remotely. Technical details are known, but no exploit is available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 08/22/2026).

Upgrading to version 7.1.9 eliminates this vulnerability. Applying the patch 131ab677b03349a5ae48da8722ec7075b37ec66e/1acef6d85bfd98bd9dfe1f08bffa397a4dda8a6f is able to eliminate this problem.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-64416). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.1.0
• 7.1.1
• 7.1.2
• 7.1.3
• 7.1.4
• 7.1.5
• 7.1.6
• 7.1.7
• 7.1.8

License

• open-source

Website

• Vendor: https://www.kernel.org/

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If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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