{"id":"CVE-2023-53311","state":"PUBLISHED","title":"nilfs2: fix use-after-free of nilfs_root in dirtying inodes via iput","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnilfs2: fix use-after-free of nilfs_root in dirtying inodes via iput\n\nDuring unmount process of nilfs2, nothing holds nilfs_root structure after\nnilfs2 detaches its writer in nilfs_detach_log_writer().  Previously,\nnilfs_evict_inode() could cause use-after-free read for nilfs_root if\ninodes are left in \"garbage_list\" and released by nilfs_dispose_list at\nthe end of nilfs_detach_log_writer(), and this bug was fixed by commit\n9b5a04ac3ad9 (\"nilfs2: fix use-after-free bug of nilfs_root in\nnilfs_evict_inode()\").\n\nHowever, it turned out that there is another possibility of UAF in the\ncall path where mark_inode_dirty_sync() is called from iput():\n\nnilfs_detach_log_writer()\n  nilfs_dispose_list()\n    iput()\n      mark_inode_dirty_sync()\n        __mark_inode_dirty()\n          nilfs_dirty_inode()\n            __nilfs_mark_inode_dirty()\n              nilfs_load_inode_block() --> causes UAF of nilfs_root struct\n\nThis can happen after commit 0ae45f63d4ef (\"vfs: add support for a\nlazytime mount option\"), which changed iput() to call\nmark_inode_dirty_sync() on its final reference if i_state has I_DIRTY_TIME\nflag and i_nlink is non-zero.\n\nThis issue appears after commit 28a65b49eb53 (\"nilfs2: do not write dirty\ndata after degenerating to read-only\") when using the syzbot reproducer,\nbut the issue has potentially existed before.\n\nFix this issue by adding a \"purging flag\" to the nilfs structure, setting\nthat flag while disposing the \"garbage_list\" and checking it in\n__nilfs_mark_inode_dirty().\n\nUnlike commit 9b5a04ac3ad9 (\"nilfs2: fix use-after-free bug of nilfs_root\nin nilfs_evict_inode()\"), this patch does not rely on ns_writer to\ndetermine whether to skip operations, so as not to break recovery on\nmount.  The nilfs_salvage_orphan_logs routine dirties the buffer of\nsalvaged data before attaching the log writer, so changing\n__nilfs_mark_inode_dirty() to skip the operation when ns_writer is NULL\nwill cause recovery write to fail.  The purpose of using the cleanup-only\nflag is to allow for narrowing of such conditions.","publishedAt":"2025-09-16T16:11:49.099Z","updatedAt":"2026-08-05T09:13:26.871Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"0ae45f63d4ef8d8eeec49c7d8b44a1775fff13e8","status":"affected","lessThan":"11afd67f1b3c28eb216e50a3ca8dbcb69bb71793","versionType":"git"},{"version":"0ae45f63d4ef8d8eeec49c7d8b44a1775fff13e8","status":"affected","lessThan":"a3c3b4cbf9b8554120fb230e6516e980c6277487","versionType":"git"},{"version":"0ae45f63d4ef8d8eeec49c7d8b44a1775fff13e8","status":"affected","lessThan":"d2c539c216cce74837a9cf5804eb205939b82227","versionType":"git"},{"version":"0ae45f63d4ef8d8eeec49c7d8b44a1775fff13e8","status":"affected","lessThan":"37207240872456fbab44a110bde6640445233963","versionType":"git"},{"version":"0ae45f63d4ef8d8eeec49c7d8b44a1775fff13e8","status":"affected","lessThan":"3645510cf926e6af2f4d44899370d7e5331c93bd","versionType":"git"},{"version":"0ae45f63d4ef8d8eeec49c7d8b44a1775fff13e8","status":"affected","lessThan":"7532ff6edbf5242376b24a95a2fefb59bb653e5a","versionType":"git"},{"version":"0ae45f63d4ef8d8eeec49c7d8b44a1775fff13e8","status":"affected","lessThan":"5828d5f5dc877dcfdd7b23102e978e2ecfd86d82","versionType":"git"},{"version":"0ae45f63d4ef8d8eeec49c7d8b44a1775fff13e8","status":"affected","lessThan":"f8654743a0e6909dc634cbfad6db6816f10f3399","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nilfs2/inode.c","fs/nilfs2/segment.c","fs/nilfs2/the_nilfs.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.0","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.0","versionType":"semver"},{"version":"4.14.323","status":"unaffected","lessThanOrEqual":"4.14.*","versionType":"semver"},{"version":"4.19.292","status":"unaffected","lessThanOrEqual":"4.19.*","versionType":"semver"},{"version":"5.4.254","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.191","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.127","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.46","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.4.11","status":"unaffected","lessThanOrEqual":"6.4.*","versionType":"semver"},{"version":"6.5","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nilfs2/inode.c","fs/nilfs2/segment.c","fs/nilfs2/the_nilfs.h"]}],"references":["https://git.kernel.org/stable/c/11afd67f1b3c28eb216e50a3ca8dbcb69bb71793","https://git.kernel.org/stable/c/a3c3b4cbf9b8554120fb230e6516e980c6277487","https://git.kernel.org/stable/c/d2c539c216cce74837a9cf5804eb205939b82227","https://git.kernel.org/stable/c/37207240872456fbab44a110bde6640445233963","https://git.kernel.org/stable/c/3645510cf926e6af2f4d44899370d7e5331c93bd","https://git.kernel.org/stable/c/7532ff6edbf5242376b24a95a2fefb59bb653e5a","https://git.kernel.org/stable/c/5828d5f5dc877dcfdd7b23102e978e2ecfd86d82","https://git.kernel.org/stable/c/f8654743a0e6909dc634cbfad6db6816f10f3399"],"weaknesses":["CWE-416"],"ingestedAt":"2026-10-29T20:06:33.064Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2023/53xxx/CVE-2023-53311.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2023-53311","state":"PUBLISHED","datePublished":"2025-09-16T16:11:49.099Z","dateUpdated":"2026-08-05T09:13:26.871Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-09-16T16:08:59.562Z"},"containers":{"cna":{"title":"nilfs2: fix use-after-free of nilfs_root in dirtying inodes via iput","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnilfs2: fix use-after-free of nilfs_root in dirtying inodes via iput\n\nDuring unmount process of nilfs2, nothing holds nilfs_root structure after\nnilfs2 detaches its writer in nilfs_detach_log_writer().  Previously,\nnilfs_evict_inode() could cause use-after-free read for nilfs_root if\ninodes are left in \"garbage_list\" and released by nilfs_dispose_list at\nthe end of nilfs_detach_log_writer(), and this bug was fixed by commit\n9b5a04ac3ad9 (\"nilfs2: fix use-after-free bug of nilfs_root in\nnilfs_evict_inode()\").\n\nHowever, it turned out that there is another possibility of UAF in the\ncall path where mark_inode_dirty_sync() is called from iput():\n\nnilfs_detach_log_writer()\n  nilfs_dispose_list()\n    iput()\n      mark_inode_dirty_sync()\n        __mark_inode_dirty()\n          nilfs_dirty_inode()\n            __nilfs_mark_inode_dirty()\n              nilfs_load_inode_block() --> causes UAF of nilfs_root struct\n\nThis can happen after commit 0ae45f63d4ef (\"vfs: add support for a\nlazytime mount option\"), which changed iput() to call\nmark_inode_dirty_sync() on its final reference if i_state has I_DIRTY_TIME\nflag and i_nlink is non-zero.\n\nThis issue appears after commit 28a65b49eb53 (\"nilfs2: do not write dirty\ndata after degenerating to read-only\") when using the syzbot reproducer,\nbut the issue has potentially existed before.\n\nFix this issue by adding a \"purging flag\" to the nilfs structure, setting\nthat flag while disposing the \"garbage_list\" and checking it in\n__nilfs_mark_inode_dirty().\n\nUnlike commit 9b5a04ac3ad9 (\"nilfs2: fix use-after-free bug of nilfs_root\nin nilfs_evict_inode()\"), this patch does not rely on ns_writer to\ndetermine whether to skip operations, so as not to break recovery on\nmount.  The nilfs_salvage_orphan_logs routine dirties the buffer of\nsalvaged data before attaching the log writer, so changing\n__nilfs_mark_inode_dirty() to skip the operation when ns_writer is NULL\nwill cause recovery write to fail.  The purpose of using the cleanup-only\nflag is to allow for narrowing of such conditions."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"0ae45f63d4ef8d8eeec49c7d8b44a1775fff13e8","status":"affected","lessThan":"11afd67f1b3c28eb216e50a3ca8dbcb69bb71793","versionType":"git"},{"version":"0ae45f63d4ef8d8eeec49c7d8b44a1775fff13e8","status":"affected","lessThan":"a3c3b4cbf9b8554120fb230e6516e980c6277487","versionType":"git"},{"version":"0ae45f63d4ef8d8eeec49c7d8b44a1775fff13e8","status":"affected","lessThan":"d2c539c216cce74837a9cf5804eb205939b82227","versionType":"git"},{"version":"0ae45f63d4ef8d8eeec49c7d8b44a1775fff13e8","status":"affected","lessThan":"37207240872456fbab44a110bde6640445233963","versionType":"git"},{"version":"0ae45f63d4ef8d8eeec49c7d8b44a1775fff13e8","status":"affected","lessThan":"3645510cf926e6af2f4d44899370d7e5331c93bd","versionType":"git"},{"version":"0ae45f63d4ef8d8eeec49c7d8b44a1775fff13e8","status":"affected","lessThan":"7532ff6edbf5242376b24a95a2fefb59bb653e5a","versionType":"git"},{"version":"0ae45f63d4ef8d8eeec49c7d8b44a1775fff13e8","status":"affected","lessThan":"5828d5f5dc877dcfdd7b23102e978e2ecfd86d82","versionType":"git"},{"version":"0ae45f63d4ef8d8eeec49c7d8b44a1775fff13e8","status":"affected","lessThan":"f8654743a0e6909dc634cbfad6db6816f10f3399","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nilfs2/inode.c","fs/nilfs2/segment.c","fs/nilfs2/the_nilfs.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.0","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.0","versionType":"semver"},{"version":"4.14.323","status":"unaffected","lessThanOrEqual":"4.14.*","versionType":"semver"},{"version":"4.19.292","status":"unaffected","lessThanOrEqual":"4.19.*","versionType":"semver"},{"version":"5.4.254","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.191","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.127","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.46","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.4.11","status":"unaffected","lessThanOrEqual":"6.4.*","versionType":"semver"},{"version":"6.5","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nilfs2/inode.c","fs/nilfs2/segment.c","fs/nilfs2/the_nilfs.h"]}],"references":[{"url":"https://git.kernel.org/stable/c/11afd67f1b3c28eb216e50a3ca8dbcb69bb71793"},{"url":"https://git.kernel.org/stable/c/a3c3b4cbf9b8554120fb230e6516e980c6277487"},{"url":"https://git.kernel.org/stable/c/d2c539c216cce74837a9cf5804eb205939b82227"},{"url":"https://git.kernel.org/stable/c/37207240872456fbab44a110bde6640445233963"},{"url":"https://git.kernel.org/stable/c/3645510cf926e6af2f4d44899370d7e5331c93bd"},{"url":"https://git.kernel.org/stable/c/7532ff6edbf5242376b24a95a2fefb59bb653e5a"},{"url":"https://git.kernel.org/stable/c/5828d5f5dc877dcfdd7b23102e978e2ecfd86d82"},{"url":"https://git.kernel.org/stable/c/f8654743a0e6909dc634cbfad6db6816f10f3399"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The UAF is reached only through local nilfs2 mount/unmount teardown (nilfs_put_super→nilfs_detach_log_writer→nilfs_dispose_list→iput); nothing in this path processes network or peer-supplied packets.\nAC:L - Free-then-use is a fixed sequential ordering inside nilfs_detach_log_writer (nilfs_segctor_destroy frees nilfs_root via nilfs_put_root, then nilfs_dispose_list uses it), not a race; the attacker controls the crafted image and dirty-inode preconditions, and syzbot reproduced it reliably.\nPR:L - An unprivileged local desktop/kiosk user suffices: udisks2/polkit auto-mounts and ejects removable nilfs2 media on the session user's behalf, and stranding inodes on ns_dirty_files uses ordinary unprivileged VFS operations—matching PR:L for the same-family nilfs2 UAF CVE-2023-53804.\nUI:N - On an auto-mounting host the attacker supplies the image, dirties inodes (I_DIRTY_TIME/lazytime path), and triggers eject/unmount themselves; no separate victim action is required.\nS:U - The freed nilfs_root/ifile objects and any resulting heap corruption remain within the kernel's own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - After kfree(root), nilfs_load_inode_block reads ii->i_root->ifile from reclaimable kmalloc-256 slab memory and feeds that pointer into nilfs_ifile_get_inode_block/nilfs_update_inode, so a groomed replacement yields an attacker-chosen inode pointer and arbitrary kernel memory disclosure.\nI:H - __nilfs_mark_inode_dirty continues through nilfs_update_inode (writes raw inode contents via the attacker-controlled ifile) and nilfs_mdt_mark_dirty(ii->i_root->ifile), giving write primitives through the reclaimed object suitable for control-flow hijacking.\nA:H - This is a KASAN-confirmed slab use-after-free; dereferencing the freed nilfs_root during unmount readily oopses or panics the kernel even without successful exploitation."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T09:13:26.871Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"4.14.323"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"4.19.292"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"5.4.254"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"5.10.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"5.15.127"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"6.1.46"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"6.4.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"6.5"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":7.8,"attackVector":"LOCAL","baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","integrityImpact":"HIGH","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"HIGH","privilegesRequired":"LOW","confidentialityImpact":"HIGH"}},{"other":{"type":"ssvc","content":{"id":"CVE-2023-53311","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-01-14T18:24:44.425794Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-416","lang":"en","type":"CWE","description":"CWE-416 Use After Free"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-01-14T18:32:57.096Z"}}]}}}