Vulnerability in Linux
CVE-2025-38085
In the Linux kernel, the following vulnerability has been resolved: mm/hugetlb: fix huge_pmd_unshare() vs GUP-fast race huge_pmd_unshare() drops a reference on a page table that may have previously been shared across processes, potentially turning it into a normal page table used in another process in which unrelated VMAs can afterwards be installed. If this happens in the middle of a concurrent gup_fast(), gup_fast() could end up walking the page tables of another process. While I don't see any way in which that immediately leads to kernel memory corruption, it is really weird and unexpected. Fix it with an explicit broadcast IPI through tlb_remove_table_sync_one(), just like we do in khugepaged when removing page tables for a THP collapse.
Vulnerability class: Race Condition
EPSS: 0.001 (1.7th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
Affected products
- Linux — versions 39dde65c9940c97fcd178a3d2b1c57ed8b7b68aa, 2.6.20, 0
- Linux Linux_kernel
- Debian Debian_linux — versions 11.0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Patch)
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Patch)
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Patch)
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Patch)
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Patch)
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Patch)
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Patch)
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Third Party Advisory)
- af854a3a-2127-422b-91ae-364da2661108 (Third Party Advisory)
- af854a3a-2127-422b-91ae-364da2661108 (Third Party Advisory)
Frequently asked questions
- What is CVE-2025-38085?
- CVE-2025-38085 is a high-severity vulnerability in Linux, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 7.8/10. Published 2025-06-28.
- How severe is CVE-2025-38085?
- High severity. CVSS v3 base score is 7.8 out of 10.
- Is CVE-2025-38085 known to be exploited?
- 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.