{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2025-21908 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2025-21908 is a medium-severity denial of service vulnerability in Linux kernel, published on 1 Apr 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-2025-21908 and fix it if it is affected.\n\nWhat it is: CVE-2025-21908 is a medium-severity denial of service vulnerability in Linux kernel, published on 1 Apr 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-2025-21908 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-2025-21908/ (Markdown: https://insights.sbomify.com/CVE-2025-21908/index.md)","id":"CVE-2025-21908","markdown":"https://insights.sbomify.com/CVE-2025-21908/index.md","name":"CVE-2025-21908","record":{"aliases":["AZL-60352","BELL-CVE-2025-21908","DEBIAN-CVE-2025-21908","GHSA-6m8x-cvmh-fpwm","ROOT-OS-UBUNTU-2204-CVE-2025-21908","ROOT-OS-UBUNTU-2404-CVE-2025-21908","UBUNTU-CVE-2025-21908"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A deadlock in the Linux kernel's NFS module can cause system hangs when kcompactd triggers writeback, leading to denial of service.","user_interaction":"not_required","vuln_class":"denial_of_service"},"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":[{"id":"CWE-667","name":"Improper Locking"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nNFS: fix nfs_release_folio() to not deadlock via kcompactd writeback\n\nAdd PF_KCOMPACTD flag and current_is_kcompactd() helper to check for it so\nnfs_release_folio() can skip calling nfs_wb_folio() from kcompactd.\n\nOtherwise NFS can deadlock waiting for kcompactd enduced writeback which\nrecurses back to NFS (which triggers writeback to NFSD via NFS loopback\nmount on the same host, NFSD blocks waiting for XFS's call to\n__filemap_get_folio):\n\n6070.550357] INFO: task kcompactd0:58 blocked for more than 4435 seconds.\n\n{---\n[58] \"kcompactd0\"\n[\u003c0\u003e] folio_wait_bit+0xe8/0x200\n[\u003c0\u003e] folio_wait_writeback+0x2b/0x80\n[\u003c0\u003e] nfs_wb_folio+0x80/0x1b0 [nfs]\n[\u003c0\u003e] nfs_release_folio+0x68/0x130 [nfs]\n[\u003c0\u003e] split_huge_page_to_list_to_order+0x362/0x840\n[\u003c0\u003e] migrate_pages_batch+0x43d/0xb90\n[\u003c0\u003e] migrate_pages_sync+0x9a/0x240\n[\u003c0\u003e] migrate_pages+0x93c/0x9f0\n[\u003c0\u003e] compact_zone+0x8e2/0x1030\n[\u003c0\u003e] compact_node+0xdb/0x120\n[\u003c0\u003e] kcompactd+0x121/0x2e0\n[\u003c0\u003e] kthread+0xcf/0x100\n[\u003c0\u003e] ret_from_fork+0x31/0x40\n[\u003c0\u003e] ret_from_fork_asm+0x1a/0x30\n---}\n\n[akpm@linux-foundation.org: fix build]","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":"NFS: fix nfs_release_folio() to not deadlock via kcompactd writeback","id":"CVE-2025-21908","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"denial_of_service","year":"2025"},"n_packages":0,"n_references":4,"next":{"headline":"wifi: nl80211: reject cooked mode if it is set along with other flags","id":"CVE-2025-21909"},"packages":[],"prev":{"headline":"mm: memory-failure: update ttu flag inside unmap_poisoned_folio","id":"CVE-2025-21907"},"products":["Linux"],"published":"2025-04-01","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":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-05-11","vendors":["Linux"]},"summary":"A deadlock in the Linux kernel's NFS module can cause system hangs when kcompactd triggers writeback, leading to denial of service.","url":"https://insights.sbomify.com/CVE-2025-21908/"}