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Vulnerabilities

Vulnerability · CVE-2025-38084

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 tabl

Published Jun 28, 2025 · catalog updated Oct 15, 2026 · Linux Linux

Check if you run it

No confirmed exploitation is on record for CVE-2025-38084. EPSS is 0.20%. Act only if a listed version of Linux Linux is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High7.8
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.20%
Remediation
Advisory link
Affected products
cpe debian/debian linux · cpe linux/linux kernel · vendor Linux Linux patch: 6.15.4

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. [jannh@google.com: v2]

Are you affected?

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  • cpe debian/debian linux11.0
  • cpe linux/linux kernelversion unspecified
  • vendor Linux Linux patch: 6.15.4patch: 6.15.4

How to fix CVE-2025-38084

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2025-38084. EPSS is 0.20%. Act only if a listed version of Linux Linux is installed.

Which versions are affected?

Compare what you have installed with debian/debian linux 11.0; Linux Linux patch: 6.15.4 patch: 6.15.4. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.20%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Jun 28, 2025 · NIST NVD

    Detected

    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 t

  2. Oct 15, 2026 · NIST NVD

    Updated

    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 t

Sources

  • CVE.orgVulnerability recordCVE-2025-38084

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2025-38084

    30-day exploitation probability 0.2%

    first.org
  • EUVDVulnerability recordEUVD-2025-19449

    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 -

    euvd.enisa.europa.eu
  • NIST NVDVulnerability recordCVE-2025-38084

    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 take

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.