# CVE-2026-74729: soc: aspeed: lpc-snoop: Fix usercopy overflow in snoop_file_read

CVE-2026-74729 is fixed in linux on 1 platform, first by DEBIAN-CVE-2026-74729, released September 4, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-74729
- Priority: Routine
- CVSS: 6.3 (Moderate)
- EPSS: 0.0019
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 22, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-74729

## Description

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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 13.5 (trixie) | 6.12.115-2 | [DEBIAN-CVE-2026-74729](https://patchblox.com/security/data/fix/linux/debian-cve-2026-74729.md) | Sep 4, 2026 |
| Linux | linux Debian 14 | 7.1.9-1 | [DEBIAN-CVE-2026-74729](https://patchblox.com/security/data/fix/linux/debian-cve-2026-74729.md) | Sep 4, 2026 |

---

Data as of 2026-11-08T13:06:02Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.