{"id":"CVE-2025-71090","state":"PUBLISHED","title":"nfsd: fix nfsd_file reference leak in nfsd4_add_rdaccess_to_wrdeleg()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix nfsd_file reference leak in nfsd4_add_rdaccess_to_wrdeleg()\n\nnfsd4_add_rdaccess_to_wrdeleg() unconditionally overwrites\nfp->fi_fds[O_RDONLY] with a newly acquired nfsd_file. However, if\nthe client already has a SHARE_ACCESS_READ open from a previous OPEN\noperation, this action overwrites the existing pointer without\nreleasing its reference, orphaning the previous reference.\n\nAdditionally, the function originally stored the same nfsd_file\npointer in both fp->fi_fds[O_RDONLY] and fp->fi_rdeleg_file with\nonly a single reference. When put_deleg_file() runs, it clears\nfi_rdeleg_file and calls nfs4_file_put_access() to release the file.\n\nHowever, nfs4_file_put_access() only releases fi_fds[O_RDONLY] when\nthe fi_access[O_RDONLY] counter drops to zero. If another READ open\nexists on the file, the counter remains elevated and the nfsd_file\nreference from the delegation is never released. This potentially\ncauses open conflicts on that file.\n\nThen, on server shutdown, these leaks cause __nfsd_file_cache_purge()\nto encounter files with an elevated reference count that cannot be\ncleaned up, ultimately triggering a BUG() in kmem_cache_destroy()\nbecause there are still nfsd_file objects allocated in that cache.","publishedAt":"2026-01-13T15:34:51.777Z","updatedAt":"2026-08-05T12:11:59.817Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"e7a8ebc305f26cab608e59a916a4ae89d6656c5f","status":"affected","lessThan":"c07dc84ed67c5a182273171639bacbbb87c12175","versionType":"git"},{"version":"e7a8ebc305f26cab608e59a916a4ae89d6656c5f","status":"affected","lessThan":"8072e34e1387d03102b788677d491e2bcceef6f5","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nfsd/nfs4state.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.17","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.17","versionType":"semver"},{"version":"6.18.4","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nfsd/nfs4state.c"]}],"references":["https://git.kernel.org/stable/c/c07dc84ed67c5a182273171639bacbbb87c12175","https://git.kernel.org/stable/c/8072e34e1387d03102b788677d491e2bcceef6f5"],"weaknesses":[],"ingestedAt":"2026-10-29T20:10:04.440Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/71xxx/CVE-2025-71090.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-71090","state":"PUBLISHED","datePublished":"2026-01-13T15:34:51.777Z","dateUpdated":"2026-08-05T12:11:59.817Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-01-13T15:30:19.649Z"},"containers":{"cna":{"title":"nfsd: fix nfsd_file reference leak in nfsd4_add_rdaccess_to_wrdeleg()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix nfsd_file reference leak in nfsd4_add_rdaccess_to_wrdeleg()\n\nnfsd4_add_rdaccess_to_wrdeleg() unconditionally overwrites\nfp->fi_fds[O_RDONLY] with a newly acquired nfsd_file. However, if\nthe client already has a SHARE_ACCESS_READ open from a previous OPEN\noperation, this action overwrites the existing pointer without\nreleasing its reference, orphaning the previous reference.\n\nAdditionally, the function originally stored the same nfsd_file\npointer in both fp->fi_fds[O_RDONLY] and fp->fi_rdeleg_file with\nonly a single reference. When put_deleg_file() runs, it clears\nfi_rdeleg_file and calls nfs4_file_put_access() to release the file.\n\nHowever, nfs4_file_put_access() only releases fi_fds[O_RDONLY] when\nthe fi_access[O_RDONLY] counter drops to zero. If another READ open\nexists on the file, the counter remains elevated and the nfsd_file\nreference from the delegation is never released. This potentially\ncauses open conflicts on that file.\n\nThen, on server shutdown, these leaks cause __nfsd_file_cache_purge()\nto encounter files with an elevated reference count that cannot be\ncleaned up, ultimately triggering a BUG() in kmem_cache_destroy()\nbecause there are still nfsd_file objects allocated in that cache."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"e7a8ebc305f26cab608e59a916a4ae89d6656c5f","status":"affected","lessThan":"c07dc84ed67c5a182273171639bacbbb87c12175","versionType":"git"},{"version":"e7a8ebc305f26cab608e59a916a4ae89d6656c5f","status":"affected","lessThan":"8072e34e1387d03102b788677d491e2bcceef6f5","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nfsd/nfs4state.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.17","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.17","versionType":"semver"},{"version":"6.18.4","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nfsd/nfs4state.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/c07dc84ed67c5a182273171639bacbbb87c12175"},{"url":"https://git.kernel.org/stable/c/8072e34e1387d03102b788677d491e2bcceef6f5"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:N - The vulnerable path processes remotely supplied NFSv4.1 COMPOUND OPEN requests through the kernel NFS server. An attacker can trigger it over the network against an exposed NFS export.\nAC:L - The attacker can deterministically retain a READ open using WANT_NO_DELEG and then request an uncontended WRITE-only open that receives a write delegation. No race or condition outside the attacker's control is required.\nPR:N - A permissive read-write export using AUTH_SYS or AUTH_NULL can allow an unauthenticated client to establish a session and open an anonymous or world-accessible file. No pre-existing target-system privileges are required in this reasonable deployment.\nUI:N - The malicious client alone can issue the OPEN, DELEGRETURN, and CLOSE operations needed to create repeatable leaks. No victim user action is required.\nS:U - The leak and resulting denial of service remain within the NFS server and host kernel security authority. No virtualization, sandbox, or other security boundary is crossed.\nC:N - The bug retains valid nfsd_file objects and does not free, over-read, or expose their contents. It provides no memory-disclosure primitive.\nI:N - The overwritten pointer causes an orphaned reference rather than a dangling pointer or memory corruption. It provides no arbitrary write, control-flow hijack, or data-modification primitive.\nA:H - The leak can be repeated across attacker-accessible files, retaining file-cache objects and causing resource exhaustion or open conflicts. During final nfsd cache teardown, the remaining objects trigger the slab BUG/WARN path and can panic systems configured to treat warnings as fatal."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:11:59.817Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.17","versionEndExcluding":"6.18.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.17","versionEndExcluding":"6.19"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}