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TI-2025-25425 Aliases CVE-2025-38084GHSA-mfp4-4cfm-v388

mm/hugetlb: unshare page tables during VMA split, not before

Priority LOW 35Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 10 fixed, 3 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.

Summary

In the Linux kernel, the following vulnerability has been resolved: mm/hugetlb: unshare page tables during VMA split, not before Currently, __split_vma() triggers hugetlb page table unsharing through vm_ops->may_split(). This happens before the VMA lock and rmap locks are taken - which is too early, it allows racing VMA-locked page faults in our process and racing rmap walks from other processes to cause page tables to be shared again before we actually perform the split. Fix it by explicitly calling into the hugetlb unshare logic from __split_vma() in the same place where THP splitting also happens. At that point, both the VMA and the rmap(s) are write-locked. An annoying detail is that we can now call into the helper hugetlb_unshare_pmds() from two different locking contexts: 1. from hugetlb_split(), holding: - mmap lock (exclusively) - VMA lock - file rmap lock (exclusively) 2. hugetlb_unshare_all_pmds(), which I think is designed to be able to call us with only the mmap lock held (in shared mode), but currently only runs while holding mmap lock (exclusively) and VMA lock Backporting note: This commit fixes a racy protection that was introduced in commit b30c14cd6102 ("hugetlb: unshare some PMDs when splitting VMAs"); that commit claimed to fix an issue introduced in 5.13, but it should actually also go all the way back. [[email protected]: v2]

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00214 11th percentileScored 2026-11-07
Fix Partial Linux (Linux): 5.10.239, 5.15.186, 6.1.142 +4Red Hat: 2 advisoriesRed Hat: 10 fixed, 3 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux2.6.20 and later5.10.239, 5.15.186, 6.1.142, 6.6.95, 6.12.35, 6.15.4, 6.16Patch availableCNA
  • Linux VendorLinux Affected 2.6.20 and later Fixed in 5.10.239, 5.15.186, 6.1.142, 6.6.95, 6.12.35, 6.15.4, 6.16 Patch available CNA

CPE configurations NVD · 2

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*2.6.20 to before 5.10.239; 5.11 to before 5.15.186; 5.16 to before 6.1.142; 6.2 to before 6.6.95; 6.7 to before 6.12.35; 6.13 to before 6.15.4VulnerableLinux
cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*11.0VulnerableDebian
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 2.6.20 to before 5.10.239; 5.11 to before 5.15.186; 5.16 to before 6.1.142; 6.2 to before 6.6.95; 6.7 to before 6.12.35; 6.13 to before 6.15.4 Vulnerable ·Linux
  • cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* Versions 11.0 Vulnerable ·Debian

Remediation

  • Fix · CNA Linux (Linux) Fixed in 5.10.239, 5.15.186, 6.1.142, 6.6.95, 6.12.35, 6.15.4, 6.16

Red Hat 2 advisories

  • RHSA-2025:13962 Released 2025-08-18 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-570.35.1.el9_6, kernel-64k-debug-devel-matched-5.14.0-570.35.1.el9_6, kernel-64k-devel-5.14.0-570.35.1.el9_6 +12
    • Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-570.35.1.el9_6, kernel-64k-5.14.0-570.35.1.el9_6, kernel-64k-core-5.14.0-570.35.1.el9_6 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-570.35.1.el9_6, libperf-5.14.0-570.35.1.el9_6
    • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-570.35.1.el9_6, kernel-rt-64k-5.14.0-570.35.1.el9_6, kernel-rt-64k-core-5.14.0-570.35.1.el9_6 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-570.35.1.el9_6, kernel-rt-core-5.14.0-570.35.1.el9_6, kernel-rt-debug-5.14.0-570.35.1.el9_6 +11
  • RHSA-2025:13598 Released 2025-08-11 · Red Hat rating Moderate
    kernel security update
    • Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-55.27.1.el10_0, kernel-64k-debug-devel-matched-6.12.0-55.27.1.el10_0, kernel-64k-devel-6.12.0-55.27.1.el10_0 +12
    • Red Hat Enterprise Linux BaseOS (v. 10) kernel-6.12.0-55.27.1.el10_0, kernel-64k-6.12.0-55.27.1.el10_0, kernel-64k-core-6.12.0-55.27.1.el10_0 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-55.27.1.el10_0, libperf-6.12.0-55.27.1.el10_0
    • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt-6.12.0-55.27.1.el10_0, kernel-rt-64k-6.12.0-55.27.1.el10_0, kernel-rt-64k-core-6.12.0-55.27.1.el10_0 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt-6.12.0-55.27.1.el10_0, kernel-rt-core-6.12.0-55.27.1.el10_0, kernel-rt-debug-6.12.0-55.27.1.el10_0 +11

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 7AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 8AffectedNo fix planned: Will not fix
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2025:13598
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2025:13962
Red Hat Enterprise Linux BaseOS (v. 10)Fixed RHSA-2025:13598
Red Hat Enterprise Linux BaseOS (v. 9)Fixed RHSA-2025:13962
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2025:13598
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)Fixed RHSA-2025:13962
Red Hat Enterprise Linux Real Time (v. 10)Fixed RHSA-2025:13598
Red Hat Enterprise Linux Real Time (v. 9)Fixed RHSA-2025:13962
Red Hat Enterprise Linux Real Time for NFV (v. 10)Fixed RHSA-2025:13598
Red Hat Enterprise Linux Real Time for NFV (v. 9)Fixed RHSA-2025:13962
Not affected: 1 product
  • Red Hat Enterprise Linux 9

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-38084
  2. 2026-10-03 Alias added: GHSA-mfp4-4cfm-v388
  3. 2026-10-16 CISA SSVC decision points changed

References

Patch 7

Advisory 3

  • TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
  • TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
  • TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
  • TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
  • TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
See all 15278 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences