{ "document": { "category": "csaf_base", "csaf_version": "2.0", "distribution": { "tlp": { "label": "WHITE" } }, "lang": "en", "notes": [ { "category": "legal_disclaimer", "text": "The Netherlands Cyber Security Center (henceforth: NCSC-NL) maintains this portal to enhance access to its information and vulnerabilities. The use of this information is subject to the following terms and conditions:\n\nThe vulnerabilities disclosed in this portal are gathered by NCSC-NL from a variety of open sources, which the user can retrieve from other platforms. NCSC-NL makes every reasonable effort to ensure that the content of this portal is kept up to date, and that it is accurate and complete. Nevertheless, NCSC-NL cannot entirely rule out the possibility of errors, and therefore cannot give any warranty in respect of its completeness, accuracy or real-time keeping up-to-date. NCSC-NL does not control nor guarantee the accuracy, relevance, timeliness or completeness of information obtained from these external sources. The vulnerabilities disclosed in this portal are intended solely for the convenience of professional parties to take appropriate measures to manage the risks posed to the cybersecurity. No rights can be derived from the information provided therein.\n\nNCSC-NL and the Kingdom of the Netherlands assume no legal liability or responsibility for any damage resulting from either the use or inability of use of the vulnerabilities disclosed in this portal. This includes damage resulting from the inaccuracy of incompleteness of the information contained in it.\nThe information on this page is subject to Dutch law. All disputes related to or arising from the use of this portal regarding the disclosure of vulnerabilities will be submitted to the competent court in The Hague. This choice of means also applies to the court in summary proceedings." } ], "publisher": { "category": "coordinator", "contact_details": "cert@ncsc.nl", "name": "National Cyber Security Centre", "namespace": "https://www.ncsc.nl/" }, "title": "CVE-2026-31404", "tracking": { "current_release_date": "2026-04-03T16:51:55.577674Z", "generator": { "date": "2026-02-17T15:00:00Z", "engine": { "name": "V.E.L.M.A", "version": "1.7" } }, "id": "CVE-2026-31404", "initial_release_date": "2026-04-03T15:39:30.731452Z", "revision_history": [ { "date": "2026-04-03T15:39:30.731452Z", "number": "1", "summary": "CVE created.| Source created.| CVE status created. (valid)| Description created for source.| Products created (3).| Products connected (5).| References created (3)." }, { "date": "2026-04-03T15:39:33.467857Z", "number": "2", "summary": "NCSC Score created." }, { "date": "2026-04-03T16:50:41.318191Z", "number": "3", "summary": "Source created.| CVE status created. (valid)| Description created for source.| References created (3)." } ], "status": "interim", "version": "3" } }, "product_tree": { "branches": [ { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:git/c224edca7af028828e2ad866b61d731b5e72b46d|<2829e80d29b627886d12b5ea40856d56b516e67d", "product": { "name": "vers:git/c224edca7af028828e2ad866b61d731b5e72b46d|<2829e80d29b627886d12b5ea40856d56b516e67d", "product_id": "CSAFPID-5992236" } }, { "category": "product_version_range", "name": "vers:git/c224edca7af028828e2ad866b61d731b5e72b46d|<48db892356d6cb80f6942885545de4a6dd8d2a29", "product": { "name": "vers:git/c224edca7af028828e2ad866b61d731b5e72b46d|<48db892356d6cb80f6942885545de4a6dd8d2a29", "product_id": "CSAFPID-5992238" } }, { "category": "product_version_range", "name": "vers:git/c224edca7af028828e2ad866b61d731b5e72b46d|name (via seq_escape) without\nholding a reference. If cache_clean removes the entry and drops the\nlast reference concurrently, the sub-objects are freed while still\nin use, producing a NULL pointer dereference in d_path.\n\nCommit 2530766492ec (\"nfsd: fix UAF when access ex_uuid or\nex_stats\") moved kfree of ex_uuid and ex_stats into the\ncall_rcu callback, but left path_put() and auth_domain_put() running\nbefore the grace period because both may sleep and call_rcu\ncallbacks execute in softirq context.\n\nReplace call_rcu/kfree_rcu with queue_rcu_work(), which defers the\ncallback until after the RCU grace period and executes it in process\ncontext where sleeping is permitted. This allows path_put() and\nauth_domain_put() to be moved into the deferred callback alongside\nthe other resource releases. Apply the same fix to expkey_put(),\nwhich has the identical pattern with ek_path and ek_client.\n\nA dedicated workqueue scopes the shutdown drain to only NFSD\nexport release work items; flushing the shared\nsystem_unbound_wq would stall on unrelated work from other\nsubsystems. nfsd_export_shutdown() uses rcu_barrier() followed\nby flush_workqueue() to ensure all deferred release callbacks\ncomplete before the export caches are destroyed.\n\nReviwed-by: Jeff Layton ", "title": "cveprojectv5 - https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/31xxx/CVE-2026-31404.json" }, { "category": "description", "text": "In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: Defer sub-object cleanup in export put callbacks\n\nsvc_export_put() calls path_put() and auth_domain_put() immediately\nwhen the last reference drops, before the RCU grace period. RCU\nreaders in e_show() and c_show() access both ex_path (via\nseq_path/d_path) and ex_client->name (via seq_escape) without\nholding a reference. If cache_clean removes the entry and drops the\nlast reference concurrently, the sub-objects are freed while still\nin use, producing a NULL pointer dereference in d_path.\n\nCommit 2530766492ec (\"nfsd: fix UAF when access ex_uuid or\nex_stats\") moved kfree of ex_uuid and ex_stats into the\ncall_rcu callback, but left path_put() and auth_domain_put() running\nbefore the grace period because both may sleep and call_rcu\ncallbacks execute in softirq context.\n\nReplace call_rcu/kfree_rcu with queue_rcu_work(), which defers the\ncallback until after the RCU grace period and executes it in process\ncontext where sleeping is permitted. This allows path_put() and\nauth_domain_put() to be moved into the deferred callback alongside\nthe other resource releases. Apply the same fix to expkey_put(),\nwhich has the identical pattern with ek_path and ek_client.\n\nA dedicated workqueue scopes the shutdown drain to only NFSD\nexport release work items; flushing the shared\nsystem_unbound_wq would stall on unrelated work from other\nsubsystems. nfsd_export_shutdown() uses rcu_barrier() followed\nby flush_workqueue() to ensure all deferred release callbacks\ncomplete before the export caches are destroyed.\n\nReviwed-by: Jeff Layton ", "title": "nvd - https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-31404" }, { "category": "other", "text": "4.1", "title": "NCSC Score" }, { "category": "other", "text": "The value of the most recent CVSS (V3) score, Is related to a product by vendor Linux", "title": "NCSC Score top decreasing factors" } ], "product_status": { "known_affected": [ "CSAFPID-2727123", "CSAFPID-5992236", "CSAFPID-5992237", "CSAFPID-5992238" ], "known_not_affected": [ "CSAFPID-2727124", "CSAFPID-5905005", "CSAFPID-5905006", "CSAFPID-5905027" ] }, "references": [ { "category": "external", "summary": "Source - cveprojectv5", "url": "https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/31xxx/CVE-2026-31404.json" }, { "category": "external", "summary": "Source - nvd", "url": "https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-31404" }, { "category": "external", "summary": "Reference - cveprojectv5; nvd", "url": "https://git.kernel.org/stable/c/2829e80d29b627886d12b5ea40856d56b516e67d" }, { "category": "external", "summary": "Reference - cveprojectv5; nvd", "url": "https://git.kernel.org/stable/c/f5ab1bec5fa18731e0b1b1e60c9a68667ac73ea2" }, { "category": "external", "summary": "Reference - cveprojectv5; nvd", "url": "https://git.kernel.org/stable/c/48db892356d6cb80f6942885545de4a6dd8d2a29" } ], "title": "CVE-2026-31404" } ] }