# CVE-2025-39910: mm/vmalloc, mm/kasan: respect gfp mask in kasan_populate_vmalloc()

CVE-2025-39910 is fixed in linux on 1 platform, first by DEBIAN-CVE-2025-39910, released October 1, 2025. It is not reported as exploited. Patch Radar priority: Urgent.

- Web page: https://patchblox.com/security/cve/CVE-2025-39910
- Priority: Urgent
- CVSS: 9.8 (Critical)
- EPSS: 0.0015
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 1, 2025
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-39910

## Description

In the Linux kernel, the following vulnerability has been resolved:  mm/vmalloc, mm/kasan: respect gfp mask in kasan_populate_vmalloc()  kasan_populate_vmalloc() and its helpers ignore the caller's gfp_mask and always allocate memory using the hardcoded GFP_KERNEL flag.  This makes them inconsistent with vmalloc(), which was recently extended to support GFP_NOFS and GFP_NOIO allocations.  Page table allocations performed during shadow population also ignore the external gfp_mask.  To preserve the intended semantics of GFP_NOFS and GFP_NOIO, wrap the apply_to_page_range() calls into the appropriate memalloc scope.  xfs calls vmalloc with GFP_NOFS, so this bug could lead to deadlock.  There was a report here https://lkml.kernel.org/r/686ea951.050a0220.385921.0016.GAE@google.com  This patch:  - Extends kasan_populate_vmalloc() and helpers to take gfp_mask;  - Passes gfp_mask down to alloc_pages_bulk() and __get_free_page();  - Enforces GFP_NOFS/NOIO semantics with memalloc_*_save()/restore()    around apply_to_page_range();  - Updates vmalloc.c and percpu allocator call sites accordingly.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 13.5 (trixie) | 6.12.115-2 | [DEBIAN-CVE-2025-39910](https://patchblox.com/security/data/fix/linux/debian-cve-2025-39910.md) | Oct 1, 2025 |
| Linux | linux Debian 14 | 6.16.8-1 | [DEBIAN-CVE-2025-39910](https://patchblox.com/security/data/fix/linux/debian-cve-2025-39910.md) | Oct 1, 2025 |

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