CVE-2025-40353

CVE-2025-40353 is a security vulnerability that is still awaiting full analysis and scoring. 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: arm64: mte: Do not warn if the page is already tagged in copy_highpage() The arm64 copy_highpage() assumes that the destination page is newly allocated and not MTE-tagged (PG_mte_tagged unset) and warns accordingly. However, following commit 060913999d7a ("mm: migrate: support poisoned recover from migrate folio"), folio_mc_copy() is called before __folio_migrate_mapping(). If the latter fails (-EAGAIN), the copy will be done again to the same destination page. Since copy_highpage() already set the PG_mte_tagged flag, this second copy will warn. Replace the WARN_ON_ONCE(page already tagged) in the arm64 copy_highpage() with a comment.

Frequently asked questions

What is CVE-2025-40353?
In the Linux kernel, the following vulnerability has been resolved: arm64: mte: Do not warn if the page is already tagged in copy_highpage() The arm64 copy_highpage() assumes that the destination page is newly allocated and not MTE-tagged (PG_mte_tagged unset) and warns accordingly. However, following commit 060913999d7a ("mm: migrate: support poisoned recover from migrate folio"), folio_mc_copy() is called before __folio_migrate_mapping(). If the latter fails (-EAGAIN), the copy will be done again to the same destination page. Since copy_highpage() already set the PG_mte_tagged flag, this second copy will warn. Replace the WARN_ON_ONCE(page already tagged) in the arm64 copy_highpage() with a comment.
Is CVE-2025-40353 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (6th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2025-40353?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-40353 have an EU (EUVD) identifier?
Yes. CVE-2025-40353 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-203634.
When was CVE-2025-40353 published?
CVE-2025-40353 was published on 2025-12-16 and last updated on 2026-06-17.

References