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…
Does this matter?
Lower severity and a low EPSS score (0.13%). Track it; it rarely justifies an emergency change on its own.
Description
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.
- CVSS 3.1
- 4.7 MEDIUMCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.13% probability · 3th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-362
- Affected
- linux/linux kernel · debian/debian linux
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/034a52b5ef57c9c8225d94e9067f3390bb33922fPatch
- https://git.kernel.org/stable/c/1013af4f585fccc4d3e5c5824d174de2257f7d6dPatch
- https://git.kernel.org/stable/c/952596b08c74e8fe9e2883d1dc8a8f54a37384ecPatch
- https://git.kernel.org/stable/c/a3d864c901a300c295692d129159fc3001a56185Patch
- https://git.kernel.org/stable/c/a6bfeb97941a9187833b526bc6cc4ff5706d0ce9Patch
- https://git.kernel.org/stable/c/b7754d3aa7bf9f62218d096c0c8f6c13698fac8bPatch
- https://git.kernel.org/stable/c/fe684290418ef9ef76630072086ee530b92f02b8Patch
- https://project-zero.issues.chromium.org/issues/420715744Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2025/10/msg00007.htmlThird Party Advisory
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.htmlThird Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.