{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2026-93221 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-93221 is a high-severity vulnerability in Linux, published on 24 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-93221 and fix it if it is affected.\n\nWhat it is: CVE-2026-93221 is a high-severity vulnerability in Linux, published on 24 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-93221 in the wild and no public exploit code.\n\nAffected product: Linux. 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-2026-93221/ (Markdown: https://insights.sbomify.com/CVE-2026-93221/index.md)","id":"CVE-2026-93221","markdown":"https://insights.sbomify.com/CVE-2026-93221/index.md","name":"CVE-2026-93221","record":{"aliases":["AZL-103946","BELL-CVE-2026-93221","DEBIAN-CVE-2026-93221","GHSA-r3mg-g23p-86c9","UBUNTU-CVE-2026-93221"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["code_execution","denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"Linux kernel NFS","requires_auth":"none","summary":"A race condition in the Linux kernel NFS server allows concurrent access to reclaim structures, leading to double-free errors and potential code execution.","user_interaction":"not_required","vuln_class":"race_condition"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[],"cvss":{"score":8.1,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: convert nfsd_net boolean flags to unsigned long flags word\n\nnfsd_net contains several boolean fields that are accessed from\nconcurrent contexts without serialization.  In particular,\nnfsd4_end_grace() guards its drain path with a plain bool:\n\n    if (nn-\u003egrace_ended)\n            return;\n    nn-\u003egrace_ended = true;\n\nThe read and the write are independent, and nothing in struct\nnfsd_net serializes them.  At least two contexts can reach this\ncode with no lock held:\n\n    laundromat path\n      laundry_wq kworker\n        nfs4_laundromat()\n          nfsd4_end_grace()\n\n    RECLAIM_COMPLETE path\n      nfsd compound kthread\n        nfsd4_reclaim_complete()\n          inc_reclaim_complete()\n            nfsd4_end_grace()\n\nBoth callers can observe grace_ended == false on different CPUs,\nboth store true, and both proceed into nfsd4_record_grace_done(),\nwhich invokes the active client_tracking_ops-\u003egrace_done callback.\nFor tracking ops that drain reclaim_str_hashtbl (legacy_tracking_ops\nvia nfsd4_recdir_purge_old, and the cld v1+ ops via\nnfsd4_cld_grace_done), grace_done calls nfs4_release_reclaim(),\nwhich walks every bucket of reclaim_str_hashtbl with no lock and\ncalls nfs4_remove_reclaim_record() (list_del + kfree) on each\nentry.  Two concurrent walkers corrupt the list and double-free\nevery nfs4_client_reclaim.  A concurrent nfsd4_find_reclaim_client()\niterating the same bucket reads through freed memory.\n\nA third call site exists in nfs4_state_start_net() on the\nskip_grace startup path, but it runs under nfsd_mutex before any\nclient has connected and before the laundromat's first delayed\nwork fires, so it cannot race with the two callers above.\n\nReplace the scattered boolean fields in nfsd_net with a single\nunsigned long flags word and an enum nfsd_net_flag for the bit\npositions.  The grace_ended race is fixed by using\ntest_and_set_bit(), which is atomic on all architectures.  The\nremaining flags (grace_end_forced, in_grace, somebody_reclaimed,\ntrack_reclaim_completes, nfsd_net_up, lockd_up) are converted to\nuse test_bit/set_bit/clear_bit for consistency.  This avoids\nsub-word cmpxchg issues on architectures like Hexagon that only\nsupport word-sized atomic operations.","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":"nfsd: convert nfsd_net boolean flags to unsigned long flags word","id":"CVE-2026-93221","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"race_condition","year":"2026"},"n_packages":0,"n_references":5,"next":{"headline":"signal: avoid shared siginfo namespace rewrites","id":"CVE-2026-93222"},"packages":[],"prev":{"headline":"sched_ext: Keep kick_sync waiting on the rq's own CPU","id":"CVE-2026-93220"},"products":["Linux"],"published":"2026-09-24","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-10-21","vendors":["Linux"]},"summary":"A race condition in the Linux kernel NFS server allows concurrent access to reclaim structures, leading to double-free errors and potential code execution.","url":"https://insights.sbomify.com/CVE-2026-93221/"}