CVE-2024-36881

CVE-2024-36881 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Description

In the Linux kernel, the following vulnerability has been resolved: mm/userfaultfd: reset ptes when close() for wr-protected ones Userfaultfd unregister includes a step to remove wr-protect bits from all the relevant pgtable entries, but that only covered an explicit UFFDIO_UNREGISTER ioctl, not a close() on the userfaultfd itself. Cover that too. This fixes a WARN trace. The only user visible side effect is the user can observe leftover wr-protect bits even if the user close()ed on an userfaultfd when releasing the last reference of it. However hopefully that should be harmless, and nothing bad should happen even if so. This change is now more important after the recent page-table-check patch we merged in mm-unstable (446dd9ad37d0 ("mm/page_table_check: support userfault wr-protect entries")), as we'll do sanity check on uffd-wp bits without vma context. So it's better if we can 100% guarantee no uffd-wp bit leftovers, to make sure each report will be valid.

Frequently asked questions

What is CVE-2024-36881?
In the Linux kernel, the following vulnerability has been resolved: mm/userfaultfd: reset ptes when close() for wr-protected ones Userfaultfd unregister includes a step to remove wr-protect bits from all the relevant pgtable entries, but that only covered an explicit UFFDIO_UNREGISTER ioctl, not a close() on the userfaultfd itself. Cover that too. This fixes a WARN trace. The only user visible side effect is the user can observe leftover wr-protect bits even if the user close()ed on an userfaultfd when releasing the last reference of it. However hopefully that should be harmless, and nothing bad should happen even if so. This change is now more important after the recent page-table-check patch we merged in mm-unstable (446dd9ad37d0 ("mm/page_table_check: support userfault wr-protect entries")), as we'll do sanity check on uffd-wp bits without vma context. So it's better if we can 100% guarantee no uffd-wp bit leftovers, to make sure each report will be valid.
How severe is CVE-2024-36881?
CVE-2024-36881 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2024-36881 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (15th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2024-36881?
CVE-2024-36881 primarily affects Linux Linux Kernel. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2024-36881?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2024-36881 have an EU (EUVD) identifier?
Yes. CVE-2024-36881 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-36233.
When was CVE-2024-36881 published?
CVE-2024-36881 was published on 2024-05-30 and last updated on 2026-06-17.

References

Affected products (8)

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