Vulnerability Database

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Total vulnerabilities in the database

CVE-2025-39910 — linux / linux_kernel

Improper Locking

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/[email protected]

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.
  • Published: Oct 1, 2025
  • Updated: Dec 15, 2025
  • CVE: CVE-2025-39910
  • Severity: Medium
  • Exploit:
  • CISA KEV:

CVSS v3:

  • Severity: Medium
  • Score: 5.5
  • AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CWEs:

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CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

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Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

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