{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2025-21696 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2025-21696 is a medium-severity vulnerability in Linux kernel, published on 12 Feb 2025. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2025-21696 and fix it if it is affected.\n\nWhat it is: CVE-2025-21696 is a medium-severity vulnerability in Linux kernel, published on 12 Feb 2025. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2025-21696 in the wild and no public exploit code.\n\nAffected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2025-21696/ (Markdown: https://insights.sbomify.com/CVE-2025-21696/index.md)","id":"CVE-2025-21696","markdown":"https://insights.sbomify.com/CVE-2025-21696/index.md","name":"CVE-2025-21696","record":{"aliases":["AZL-56839","BELL-CVE-2025-21696","DEBIAN-CVE-2025-21696","GHSA-6q8c-8rxm-f6fh","ROOT-OS-DEBIAN-11-CVE-2025-21696","ROOT-OS-DEBIAN-12-CVE-2025-21696","ROOT-OS-UBUNTU-2204-CVE-2025-21696","ROOT-OS-UBUNTU-2404-CVE-2025-21696","UBUNTU-CVE-2025-21696"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":true,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A kernel inconsistency in userfaultfd write-protect handling during mremap can trigger a page table check warning, potentially causing a denial of service.","user_interaction":"not_required","vuln_class":"other"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":5.5,"severity":"medium","source":"cisa-adp","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm: clear uffd-wp PTE/PMD state on mremap()\n\nWhen mremap()ing a memory region previously registered with userfaultfd as\nwrite-protected but without UFFD_FEATURE_EVENT_REMAP, an inconsistency in\nflag clearing leads to a mismatch between the vma flags (which have\nuffd-wp cleared) and the pte/pmd flags (which do not have uffd-wp\ncleared).  This mismatch causes a subsequent mprotect(PROT_WRITE) to\ntrigger a warning in page_table_check_pte_flags() due to setting the pte\nto writable while uffd-wp is still set.\n\nFix this by always explicitly clearing the uffd-wp pte/pmd flags on any\nsuch mremap() so that the values are consistent with the existing clearing\nof VM_UFFD_WP.  Be careful to clear the logical flag regardless of its\nphysical form; a PTE bit, a swap PTE bit, or a PTE marker.  Cover PTE,\nhuge PMD and hugetlb paths.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"mm: clear uffd-wp PTE/PMD state on mremap()","id":"CVE-2025-21696","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"other","year":"2025"},"n_packages":0,"n_references":3,"next":{"headline":"drm/v3d: Ensure job pointer is set to NULL after job completion","id":"CVE-2025-21697"},"packages":[],"prev":{"headline":"platform/x86: dell-uart-backlight: fix serdev race","id":"CVE-2025-21695"},"products":["Linux"],"published":"2025-02-12","related":[{"cvss_score":8.8,"headline":"Linux Kernel Out-of-Bounds Write","id":"CVE-2026-53266","kev_date_added":"2026-09-18","published":"2026-06-25"},{"cvss_score":8.8,"headline":"Linux Kernel Improper Input Validation","id":"CVE-2013-6282","kev_date_added":"2022-09-15","published":"2013-11-19"},{"cvss_score":8.4,"headline":"Linux Kernel Heap-Based Buffer Overflow","id":"CVE-2022-0185","kev_date_added":"2024-08-21","published":"2022-02-11"},{"cvss_score":8.4,"headline":"Linux Kernel Privilege Escalation","id":"CVE-2013-2094","kev_date_added":"2022-09-15","published":"2013-05-14"},{"cvss_score":7.8,"headline":"Linux Kernel Unspecified","id":"CVE-2026-53362","kev_date_added":"2026-08-27","published":"2026-07-04"},{"cvss_score":7.8,"headline":"Linux Kernel Missing Initialization of a Variable","id":"CVE-2026-46300","kev_date_added":"2026-10-28","published":"2026-05-23"},{"cvss_score":7.8,"headline":"Linux Kernel Race Condition","id":"CVE-2025-39964","kev_date_added":"2026-09-18","published":"2025-10-13"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-10-21","vendors":["Linux"]},"summary":"A kernel inconsistency in userfaultfd write-protect handling during mremap can trigger a page table check warning, potentially causing a denial of service.","url":"https://insights.sbomify.com/CVE-2025-21696/"}