CVE-2025-39836: Linux Kernel

High severity, CVSS 7.8. EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: efi: stmm: Fix incorrect buffer allocation method The communication buffer allocated by setup_mm_hdr() is later on passed to tee_shm_register_kernel_buf(). The latter expects those buffers to be contiguous pages, but setup_mm_hdr() just uses kmalloc(). That can cause various corruptions or BUGs, specifically since commit 9aec2fb0fd5e ("slab: allocate frozen pages"), though it was broken before as well. Fix this by using alloc_pages_exact() instead of kmalloc().

Affected products

• Linux Linux Kernel: from 6.8, before 6.12.45 (fixed in 6.12.45); from 6.13, before 6.16.5 (fixed in 6.16.5); version 6.17 only

Published 2025-09-16. Last modified 2026-06-17.