{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2026-90039 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-90039 is a vulnerability in Linux, published on 16 Sep 2026. 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-2026-90039 and fix it if it is affected.\n\nWhat it is: CVE-2026-90039 is a vulnerability in Linux, published on 16 Sep 2026. 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-2026-90039 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-2026-90039/ (Markdown: https://insights.sbomify.com/CVE-2026-90039/index.md)","id":"CVE-2026-90039","markdown":"https://insights.sbomify.com/CVE-2026-90039/index.md","name":"CVE-2026-90039","record":{"aliases":["BELL-CVE-2026-90039","DEBIAN-CVE-2026-90039","GHSA-m7r7-c74x-x286","UBUNTU-CVE-2026-90039"],"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":"high_privilege","summary":"A local administrator can crash the Linux kernel by triggering NFS state revocation before server threads start, causing a null pointer dereference.","user_interaction":"not_required","vuln_class":"null_dereference"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[],"cvss":{"score":null,"severity":null,"source":null,"vector":null,"version":null},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: Guard admin state-revocation walks with NFSD_NET_UP\n\nWriting to /proc/fs/nfsd/unlock_filesystem, or sending the\nNFSD_CMD_UNLOCK_FILESYSTEM or NFSD_CMD_UNLOCK_EXPORT netlink command,\nwalks the NFSv4 client hash tables to revoke open state and cancel\nasync COPY operations.  All three handlers gate that walk on\nnn-\u003enfsd_serv, but a listener added via portlist or netlink\nlistener_set sets nn-\u003enfsd_serv before any nfsd thread starts.\nnfsd_startup_net() has not yet allocated nn-\u003econf_id_hashtbl, so the\nwalkers dereference a NULL table.  A local administrator with\nCAP_SYS_ADMIN can crash the kernel this way without ever starting the\nserver.\n\nnn-\u003enfsd_serv is set when the service is created, which precedes\ntable allocation.  NFSD_NET_UP instead brackets the window where the\ntables are live: set at the end of nfsd_startup_net() and cleared in\nnfsd_shutdown_net() after they are freed, both under nfsd_mutex.\nGating the three unlock paths on NFSD_NET_UP fixes the startup-time\nNULL dereference while preserving the earlier post-shutdown\nuse-after-free fix.","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: Guard admin state-revocation walks with NFSD_NET_UP","id":"CVE-2026-90039","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"null_dereference","year":"2026"},"n_packages":0,"n_references":4,"next":{"headline":"KVM: SEV: Forcefully invalidate SNP VMSA if its backing gmem page is zapped","id":"CVE-2026-90040"},"packages":[],"prev":{"headline":"NFSD: Prevent client use-after-free during export state revocation","id":"CVE-2026-90038"},"products":["Linux"],"published":"2026-09-16","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-10-19","vendors":["Linux"]},"summary":"A local administrator can crash the Linux kernel by triggering NFS state revocation before server threads start, causing a null pointer dereference.","url":"https://insights.sbomify.com/CVE-2026-90039/"}