CVE-2025-21696
- Source
- https://nvd.nist.gov/vuln/detail/CVE-2025-21696
- Import Source
- https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-21696.json
- JSON Data
- https://api.test.osv.dev/v1/vulns/CVE-2025-21696
- Downstream
- Related
- Published
- 2025-02-12T13:27:54Z
- Modified
- 2025-10-17T21:20:21.907123Z
- Severity
-
- 5.5 (Medium) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
- Summary
- mm: clear uffd-wp PTE/PMD state on mremap()
- Details
-
In the Linux kernel, the following vulnerability has been resolved:
mm: clear uffd-wp PTE/PMD state on mremap()
When mremap()ing a memory region previously registered with userfaultfd as write-protected but without UFFDFEATUREEVENTREMAP, an inconsistency in flag clearing leads to a mismatch between the vma flags (which have uffd-wp cleared) and the pte/pmd flags (which do not have uffd-wp cleared). This mismatch causes a subsequent mprotect(PROTWRITE) to trigger a warning in pagetablecheckpteflags() due to setting the pte to writable while uffd-wp is still set.
Fix this by always explicitly clearing the uffd-wp pte/pmd flags on any such mremap() so that the values are consistent with the existing clearing of VMUFFDWP. Be careful to clear the logical flag regardless of its physical form; a PTE bit, a swap PTE bit, or a PTE marker. Cover PTE, huge PMD and hugetlb paths.
- References
Affected packages
Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Affected ranges
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced63b2d4174c4ad1f40b48d7138e71bcb564c1fe03Fixed310ac886d68de661c3a334198d8604b722d7fdf8
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced63b2d4174c4ad1f40b48d7138e71bcb564c1fe03Fixed0cef0bb836e3cfe00f08f9606c72abd72fe78ca3