{"id":"CVE-2026-22980","title":"nfsd: provide locking for v4_end_grace","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: provide locking for v4_end_grace\n\nWriting to v4_end_grace can race with server shutdown and result in\nmemory being accessed after it was freed - reclaim_str_hasht…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= 7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6 < ca97360860eb02e3ae4ba42c19b439a0fcecbf06","Linux >= 7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6 < e8bfa2401d4c51eca6e48e9b33c798828ca9df61","Linux >= 7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6 < 34eb22836e0cdba093baac66599d68c4cd245a9d","Linux >= 7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6 < 06600719d0f7a723811c45e4d51f5b742f345309","Linux >= 7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6 < ba4811c8b433bfa681729ca42cc62b6034f223b0","Linux >= 7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6 < 53f07d095e7e680c5e4569a55a019f2c0348cdc6","Linux >= 7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6 < 2857bd59feb63fcf40fe4baf55401baea6b4feb4","Linux 3.18"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-06-16T20:36:55.336499Z"},"published":"2026-01-23","updated":"2026-09-08","sourceUpdated":"2026-09-08T08:44:27.990Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-22980","references":[{"url":"https://git.kernel.org/stable/c/ca97360860eb02e3ae4ba42c19b439a0fcecbf06"},{"url":"https://git.kernel.org/stable/c/e8bfa2401d4c51eca6e48e9b33c798828ca9df61"},{"url":"https://git.kernel.org/stable/c/34eb22836e0cdba093baac66599d68c4cd245a9d"},{"url":"https://git.kernel.org/stable/c/06600719d0f7a723811c45e4d51f5b742f345309"},{"url":"https://git.kernel.org/stable/c/ba4811c8b433bfa681729ca42cc62b6034f223b0"},{"url":"https://git.kernel.org/stable/c/53f07d095e7e680c5e4569a55a019f2c0348cdc6"},{"url":"https://git.kernel.org/stable/c/2857bd59feb63fcf40fe4baf55401baea6b4feb4"}],"tags":["cve.org"],"epss":0.00149,"epssPercentile":0.04493,"ingestedAt":"2026-09-08T15:33:26.994Z","slug":"CVE-2026-22980","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: provide locking for v4_end_grace\n\nWriting to v4_end_grace can race with server shutdown and result in\nmemory being accessed after it was freed - reclaim_str_hashtbl in\nparticularly.\n\nWe cannot hold nfsd_mutex across the nfsd4_end_grace() call as that is\nheld while client_tracking_op->init() is called and that can wait for\nan upcall to nfsdcltrack which can write to v4_end_grace, resulting in a\ndeadlock.\n\nnfsd4_end_grace() is also called by the landromat work queue and this\ndoesn't require locking as server shutdown will stop the work and wait\nfor it before freeing anything that nfsd4_end_grace() might access.\n\nHowever, we must be sure that writing to v4_end_grace doesn't restart\nthe work item after shutdown has already waited for it.  For this we\nadd a new flag protected with nn->client_lock.  It is set only while it\nis safe to make client tracking calls, and v4_end_grace only schedules\nwork while the flag is set with the spinlock held.\n\nSo this patch adds a nfsd_net field \"client_tracking_active\" which is\nset as described.  Another field \"grace_end_forced\", is set when\nv4_end_grace is written.  After this is set, and providing\nclient_tracking_active is set, the laundromat is scheduled.\nThis \"grace_end_forced\" field bypasses other checks for whether the\ngrace period has finished.\n\nThis resolves a race which can result in use-after-free.\n\n## Affected\n\n- `Linux >= 7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6 < ca97360860eb02e3ae4ba42c19b439a0fcecbf06`\n- `Linux >= 7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6 < e8bfa2401d4c51eca6e48e9b33c798828ca9df61`\n- `Linux >= 7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6 < 34eb22836e0cdba093baac66599d68c4cd245a9d`\n- `Linux >= 7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6 < 06600719d0f7a723811c45e4d51f5b742f345309`\n- `Linux >= 7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6 < ba4811c8b433bfa681729ca42cc62b6034f223b0`\n- `Linux >= 7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6 < 53f07d095e7e680c5e4569a55a019f2c0348cdc6`\n- `Linux >= 7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6 < 2857bd59feb63fcf40fe4baf55401baea6b4feb4`\n- `Linux 3.18`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}