CVE-2025-38447

7.8 HIGH 0.2% exploit odds Fix listed Memory safety OS & kernel

What it is

In the Linux kernel, the following vulnerability has been resolved: mm/rmap: fix potential out-of-bounds page table access during batched unmap As pointed out by David[1], the batched unmap logic in try_to_unmap_one() may read past the end of a PTE table when a large folio's PTE mappings are not fully contained within a single page table. While this scenario might be rare, an issue triggerable from userspace must be fixed regardless of its likelihood. This patch fixes the out-of-bounds access by refactoring the logic into a new helper, folio_unmap_pte_batch(). The new helper correctly calculates the safe batch size by capping the scan at both the VMA and PMD boundaries. To simplify the code, it also supports partial batching (i.e., any number of pages from 1 up to the calculated safe maximum), as there is no strong reason to special-case for fully mapped folios.

At a glance

Exploitability: Can be exploited locally on the machine with a low-privilege account. High risk of data exposure, data tampering, service disruption.
Exploit odds: 0.2% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2025-07-25 16:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-07-30 06:23 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.2% in the next 30 days (EPSS).
Severity: 7.8 HIGH (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2025-07-25 16:15 UTC
Last modified: 2026-07-30 06:23 UTC
Exploit probability: 0.2% · EPSS, next 30 days
Weakness: CWE-125 · Out-of-bounds read
Record status: Modified

Affected

Linux Kernel < 6.15.7
Linux Kernel 6.16

Attack profile CVSS 3.1 · 7.8

Attack vector: Local
Complexity: Low
Privileges needed: Low
User interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

Raw vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Is it in your code?

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Read https://cve-list.com/agent/cve/CVE-2025-38447.md and follow it. Check whether this project is affected by CVE-2025-38447. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record