CVE-2025-39899
BaseFortify
Publication date: 2025-10-01
Last updated on: 2025-12-12
Assigner: kernel.org
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | From 6.8 (inc) to 6.12.46 (exc) |
| linux | linux_kernel | From 6.13 (inc) to 6.16.6 (exc) |
| linux | linux_kernel | 6.17 |
| linux | linux_kernel | 6.17 |
| linux | linux_kernel | 6.17 |
| linux | linux_kernel | 6.17 |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-NVD-CWE-noinfo |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability is related to the Linux kernel's memory management on 32-bit ARM systems with CONFIG_HIGHPTE enabled. The function move_pages_pte() maps page table entries (PTE) using kmap_local_page(), which requires that pages be unmapped in Last-In-First-Out (LIFO) order. However, the existing code unmapped the pages in the same order they were mapped, violating the LIFO requirement. This causes a warning in the kernel and indicates improper handling of memory mappings. The fix reverses the unmap order to respect the LIFO requirement.
How can this vulnerability impact me? :
The improper unmapping order can cause warnings and potentially unstable behavior in the kernel's memory management on affected systems. While the description does not explicitly mention crashes or security breaches, violating the LIFO unmapping order can lead to memory corruption or kernel instability, which may affect system reliability and performance.
How can this vulnerability be detected on my network or system? Can you suggest some commands?
This vulnerability can be detected by monitoring the system logs for the specific warning message generated by the kernel: 'WARNING: CPU: ... kunmap_local_indexed+0x178/0x17c addr != __fix_to_virt(FIX_KMAP_BEGIN + idx)'. You can use the command 'dmesg | grep kunmap_local_indexed' or 'journalctl -k | grep kunmap_local_indexed' to search for this warning in the kernel logs.
What immediate steps should I take to mitigate this vulnerability?
The immediate mitigation is to update the Linux kernel to a version that includes the fix for this issue, which corrects the unmapping order to follow Last-In-First-Out (LIFO) as required by kmap_local_page(). Until the update is applied, monitoring for the warning message can help identify if the issue is occurring.