CVE-2025-39836
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-09-16

Last updated on: 2025-12-01

Assigner: kernel.org

Description
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().
CVSS Scores
EPSS Scores
Probability:
Percentile:
Meta Information
Published
2025-09-16
Last Modified
2025-12-01
Generated
2026-06-16
AI Q&A
2025-09-16
EPSS Evaluated
2026-06-15
NVD
CVE-2025-39836
Affected Vendors & Products
Showing 5 associated CPEs
Vendor Product Version / Range
linux linux_kernel From 6.8 (inc) to 6.12.45 (exc)
linux linux_kernel From 6.13 (inc) to 6.16.5 (exc)
linux linux_kernel 6.17
linux linux_kernel 6.17
linux linux_kernel 6.17
Helpful Resources
Exploitability
CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-787 The product writes data past the end, or before the beginning, of the intended buffer.
Attack-Flow Graph
AI Quick Actions
Instant insights powered by AI
Executive Summary

This vulnerability involves an incorrect buffer allocation method in the Linux kernel's EFI subsystem. Specifically, the function setup_mm_hdr() allocates a communication buffer using kmalloc(), which does not guarantee contiguous memory pages. However, the buffer is later passed to tee_shm_register_kernel_buf(), which expects contiguous pages. This mismatch can lead to memory corruption or kernel bugs. The issue was fixed by changing the allocation method to alloc_pages_exact(), which ensures contiguous pages.

Impact Analysis

The vulnerability can cause various memory corruptions or kernel bugs, potentially leading to system instability, crashes, or unexpected behavior in systems running the affected Linux kernel versions.

Mitigation Strategies

To mitigate this vulnerability, update the Linux kernel to a version that includes the fix replacing kmalloc() with alloc_pages_exact() in the efi: stmm component. This ensures proper buffer allocation and prevents potential corruptions or BUGs.

Chat Assistant
Ask questions about this CVE
Hi! I’m here to help you understand CVE-2025-39836. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70
EPSS Chart