5.5

CVE-2025-21696: linux

CVSS: 5.5v3.1MediumModified
AliasesUBUNTU-CVE-2025-21696DEBIAN-CVE-2025-21696
Published 12-02-2025Last modified 11-05-2026
Open JSON

Vulnerability summary

CVE-2025-21696 is a medium (CVSS 5.5) vulnerability in linux. EPSS estimates a 0.19% chance of exploitation in the next 30 days, higher than 8.2% of scored vulnerabilities.

Overall risk
22/100
0100
Low · default modelHow is this calculated?
CVSS score
5.5/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.19%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 14 · Related 12
RHSA-2025:20095RHSA-2025:20518SUSE-SU-2025:01614-1SUSE-SU-2025:01707-1SUSE-SU-2025:01919-1SUSE-SU-2025:01951-1

Timeline

  1. 12-02-2025
    PublishedVulnerability first disclosed.
  2. 11-05-2026
    Last modifiedVulnerability information updated.

Description

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 UFFD_FEATURE_EVENT_REMAP, 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(PROT_WRITE) to trigger a warning in page_table_check_pte_flags() 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 VM_UFFD_WP. 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.

CVSS metrics

5 scores · 4 sources · 2 versions

EPSS trend

Probability

0.19%

Chance of exploitation in the next 30 days

Percentile

8%

Versus all other CVEs

30-day change

0.00 pp

From 0.19% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.19%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Ubuntu128 products
  • linuxAll versions (No fix recorded)
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded)
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ 63b2d4174c4ad1f40b48d7138e71bcb564c1fe03, < 310ac886d68de661c3a334198d8604b722d7fdf8 | ≥ 63b2d4174c4ad1f40b48d7138e71bcb564c1fe03, < 0cef0bb836e3cfe00f08f9606c72abd72fe78ca3 | 5.7
  • linux_kernel≥ 5.7, < 6.12.11 | 6.13:rc1 | 6.13:rc2 | 6.13:rc3 | 6.13:rc4 | 6.13:rc5 | 6.13:rc6 | 6.13:rc7
Debian1 product
  • linuxAll versions (No fix recorded) | < 6.12.11-1

3 vendors · 131 products

References

8 links