CVE-2025-39871
BaseFortify
Publication date: 2025-09-23
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 6.1.140 (inc) to 6.2 (exc) |
| linux | linux_kernel | From 6.6.92 (inc) to 6.6.107 (exc) |
| linux | linux_kernel | From 6.12.30 (inc) to 6.12.48 (exc) |
| linux | linux_kernel | From 6.14.8 (inc) to 6.15 (exc) |
| linux | linux_kernel | From 6.15.1 (inc) to 6.16.8 (exc) |
| linux | linux_kernel | 6.15 |
| linux | linux_kernel | 6.15 |
| linux | linux_kernel | 6.17 |
| 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-416 | The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability in the Linux kernel's dmaengine idxd driver involves an improper call to idxd_free(), which causes a duplicate put_device() call. This leads to a reference count underflow, resulting in a use-after-free condition. Essentially, the device's reference count is decremented too many times, potentially causing memory corruption or crashes during module unload.
How can this vulnerability impact me? :
The impact of this vulnerability includes potential memory corruption and use-after-free errors during the unloading of the idxd kernel module. This can lead to system instability, crashes, or security issues due to improper memory handling.
How can this vulnerability be detected on my network or system? Can you suggest some commands?
This vulnerability can be detected by monitoring kernel logs for refcount underflow warnings related to idxd_free, such as messages containing 'refcount_t: underflow; use-after-free' or warnings from refcount_warn_saturate. You can check the kernel log using commands like 'dmesg | grep refcount' or 'journalctl -k | grep refcount'.
What immediate steps should I take to mitigate this vulnerability?
The immediate mitigation is to update the Linux kernel to a version where the improper idxd_free() call has been removed, as this fix prevents the reference count underflow and potential use-after-free issues during module unload. If updating is not immediately possible, avoid unloading the idxd module to prevent triggering the vulnerability.