{"id":"CVE-2023-53311","url":"https://www.cyber-defence.io/tools/cve/CVE-2023-53311","generatedAt":"2026-10-28T09:26:57.995Z","title":"In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix use-after-free of nilfs_root in dirtying inodes via iput During unmount process of nilfs2, nothing holds nilfs_root structure after nilfs2 detaches its writer in…","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.","published":"2025-09-16T17:15:37.000Z","lastModified":"2026-06-17T06:44:49.000Z","status":"Modified","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":{"version":"3.1","score":7.8,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-416"],"affected":["linux/linux kernel"],"epss":{"score":0.00164,"percentile":0.05517,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.16%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://git.kernel.org/stable/c/11afd67f1b3c28eb216e50a3ca8dbcb69bb71793","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3645510cf926e6af2f4d44899370d7e5331c93bd","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/37207240872456fbab44a110bde6640445233963","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5828d5f5dc877dcfdd7b23102e978e2ecfd86d82","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7532ff6edbf5242376b24a95a2fefb59bb653e5a","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a3c3b4cbf9b8554120fb230e6516e980c6277487","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/d2c539c216cce74837a9cf5804eb205939b82227","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f8654743a0e6909dc634cbfad6db6816f10f3399","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2023-53311","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}