CVE-2025-38085
Vulnerability Summary
Timeline
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 Metrics
- v3.1•MEDIUM•Score: 4.7CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
- v3.1•HIGH•Score: 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Trends
Current EPSS score: 0.14%• Percentile: 3%
Techniques & Countermeasures
- CWE-362•Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.
Affected Systems
- debian•linux
< 5.10.244-1 | < 6.1.147-1 | < 6.12.35-1 | < 6.12.35-1
- debian•linux-6.1
< 6.1.153-1~deb11u1
- ubuntu•linux
all | < 5.15.0-156.166 | < 6.8.0-100.100
- ubuntu•linux-allwinner-5.19
all
- ubuntu•linux-aws
all | < 5.15.0-1092.99 | < 6.8.0-1046.49
- ubuntu•linux-aws-5.0
all
- ubuntu•linux-aws-5.11
all
- ubuntu•linux-aws-5.13
all
- ubuntu•linux-aws-5.15
< 5.15.0-1092.99~20.04.1
- ubuntu•linux-aws-5.19
all
- ubuntu•linux-aws-5.3
all
- ubuntu•linux-aws-5.4
all
- ubuntu•linux-aws-5.8
all
- ubuntu•linux-aws-6.14
< 6.14.0-1015.15~24.04.1
- ubuntu•linux-aws-6.2
all
- ubuntu•linux-aws-6.5
all
- ubuntu•linux-aws-6.8
< 6.8.0-1046.49~22.04.1
- ubuntu•linux-aws-fips
all | < 5.15.0-1092.99+fips1 | < 6.8.0-1046.49+fips1
- ubuntu•linux-aws-hwe
all
- ubuntu•linux-azure
all | all | < 5.15.0-1096.105 | < 6.8.0-1046.52
- ubuntu•linux-azure-4.15
all
- ubuntu•linux-azure-5.11
all
- ubuntu•linux-azure-5.13
all
- ubuntu•linux-azure-5.15
< 5.15.0-1096.105~20.04.1
- ubuntu•linux-azure-5.19
all
- ubuntu•linux-azure-5.3
all
- ubuntu•linux-azure-5.4
all
- ubuntu•linux-azure-5.8
all
- ubuntu•linux-azure-6.11
all
- ubuntu•linux-azure-6.14
< 6.14.0-1014.14~24.04.1
- ubuntu•linux-azure-6.2
all
- ubuntu•linux-azure-6.5
all
- ubuntu•linux-azure-6.8
< 6.8.0-1051.57~22.04.1
- ubuntu•linux-azure-edge
all
- ubuntu•linux-azure-fde
all | all | all | all
- ubuntu•linux-azure-fde-5.19
all
- ubuntu•linux-azure-fde-6.2
all
- ubuntu•linux-azure-fde-6.8
all
- ubuntu•linux-azure-fips
all | < 5.15.0-1096.105+fips1 | < 6.8.0-1046.52+fips1
- ubuntu•linux-azure-nvidia
all
- ubuntu•linux-azure-nvidia-6.14
< 6.14.0-1007.7
- ubuntu•linux-bluefield
all | all | < 5.15.0-1076.78 | < 6.8.0-1016.20
- ubuntu•linux-fips
all | < 5.15.0-156.166+fips1 | < 6.8.0-100.100+fips1
- ubuntu•linux-gcp
all | all | < 5.15.0-1092.101 | < 6.8.0-1047.50
- ubuntu•linux-gcp-4.15
all
- ubuntu•linux-gcp-5.11
all
- ubuntu•linux-gcp-5.13
all
- ubuntu•linux-gcp-5.15
< 5.15.0-1092.101~20.04.1
- ubuntu•linux-gcp-5.19
all
- ubuntu•linux-gcp-5.3
all
Showing first 50 affected entries in server-rendered view.
References (45)
- https://git.kernel.org/stable/c/952596b08c74e8fe9e2883d1dc8a8f54a37384ec
- https://git.kernel.org/stable/c/a3d864c901a300c295692d129159fc3001a56185
- https://git.kernel.org/stable/c/b7754d3aa7bf9f62218d096c0c8f6c13698fac8b
- https://git.kernel.org/stable/c/fe684290418ef9ef76630072086ee530b92f02b8
- https://git.kernel.org/stable/c/034a52b5ef57c9c8225d94e9067f3390bb33922f
- https://git.kernel.org/stable/c/a6bfeb97941a9187833b526bc6cc4ff5706d0ce9
- https://git.kernel.org/stable/c/1013af4f585fccc4d3e5c5824d174de2257f7d6d
- https://project-zero.issues.chromium.org/issues/420715744
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
- https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html
- https://ubuntu.com/security/CVE-2025-38085
- https://www.cve.org/CVERecord?id=CVE-2025-38085
- https://git.kernel.org/linus/1013af4f585fccc4d3e5c5824d174de2257f7d6d
- https://ubuntu.com/security/notices/USN-7774-1
- https://ubuntu.com/security/notices/USN-7774-2
- https://ubuntu.com/security/notices/USN-7774-3
- https://ubuntu.com/security/notices/USN-7775-1
- https://ubuntu.com/security/notices/USN-7776-1
- https://ubuntu.com/security/notices/USN-7775-2
- https://ubuntu.com/security/notices/USN-7775-3
- https://ubuntu.com/security/notices/USN-7774-4
- https://ubuntu.com/security/notices/USN-7774-5
- https://ubuntu.com/security/notices/USN-7833-1
- https://ubuntu.com/security/notices/USN-7834-1
- https://ubuntu.com/security/notices/USN-7833-2
- https://ubuntu.com/security/notices/USN-7833-3
- https://ubuntu.com/security/notices/USN-7833-4
- https://ubuntu.com/security/notices/USN-7856-1
- https://ubuntu.com/security/notices/USN-8028-1
- https://ubuntu.com/security/notices/USN-8028-2
- https://ubuntu.com/security/notices/USN-8031-1
- https://ubuntu.com/security/notices/USN-8028-3
- https://ubuntu.com/security/notices/USN-8028-4
- https://ubuntu.com/security/notices/USN-8028-5
- https://ubuntu.com/security/notices/USN-8031-2
- https://ubuntu.com/security/notices/USN-8028-6
- https://ubuntu.com/security/notices/USN-8031-3
- https://ubuntu.com/security/notices/USN-8052-1
- https://ubuntu.com/security/notices/USN-8028-7
- https://ubuntu.com/security/notices/USN-8028-8
- https://ubuntu.com/security/notices/USN-8052-2
- https://ubuntu.com/security/notices/USN-8074-1
- https://ubuntu.com/security/notices/USN-8074-2
- https://ubuntu.com/security/notices/USN-8126-1
- https://security-tracker.debian.org/tracker/CVE-2025-38085