{"id":"CVE-2023-53608","state":"PUBLISHED","title":"nilfs2: fix potential UAF of struct nilfs_sc_info in nilfs_segctor_thread()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnilfs2: fix potential UAF of struct nilfs_sc_info in nilfs_segctor_thread()\n\nThe finalization of nilfs_segctor_thread() can race with\nnilfs_segctor_kill_thread() which terminates that thread, potentially\ncausing a use-after-free BUG as KASAN detected.\n\nAt the end of nilfs_segctor_thread(), it assigns NULL to \"sc_task\" member\nof \"struct nilfs_sc_info\" to indicate the thread has finished, and then\nnotifies nilfs_segctor_kill_thread() of this using waitqueue\n\"sc_wait_task\" on the struct nilfs_sc_info.\n\nHowever, here, immediately after the NULL assignment to \"sc_task\", it is\npossible that nilfs_segctor_kill_thread() will detect it and return to\ncontinue the deallocation, freeing the nilfs_sc_info structure before the\nthread does the notification.\n\nThis fixes the issue by protecting the NULL assignment to \"sc_task\" and\nits notification, with spinlock \"sc_state_lock\" of the struct\nnilfs_sc_info.  Since nilfs_segctor_kill_thread() does a final check to\nsee if \"sc_task\" is NULL with \"sc_state_lock\" locked, this can eliminate\nthe race.","publishedAt":"2025-10-04T15:44:17.302Z","updatedAt":"2026-08-05T09:15:06.157Z","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":"9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453","status":"affected","lessThan":"034cce77d52ba013ce62b4f5258c29907eb1ada5","versionType":"git"},{"version":"9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453","status":"affected","lessThan":"0dbf0e64b91ee8fcb278aea93eb06fc7d56ecbcc","versionType":"git"},{"version":"9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453","status":"affected","lessThan":"613bf23c070d11c525268f2945aa594704a9b764","versionType":"git"},{"version":"9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453","status":"affected","lessThan":"f32297dba338dc06d62286dedb3cdbd5175b1719","versionType":"git"},{"version":"9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453","status":"affected","lessThan":"92684e02654c91a61a0b0561433b710bcece19fe","versionType":"git"},{"version":"9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453","status":"affected","lessThan":"bae009a2f1b7c2011d2e92d8c84868d315c0b97e","versionType":"git"},{"version":"9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453","status":"affected","lessThan":"b4d80bd6370b81a1725b6b8f7894802c23a14e9f","versionType":"git"},{"version":"9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453","status":"affected","lessThan":"6be49d100c22ffea3287a4b19d7639d259888e33","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nilfs2/segment.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.30","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.30","versionType":"semver"},{"version":"4.14.313","status":"unaffected","lessThanOrEqual":"4.14.*","versionType":"semver"},{"version":"4.19.281","status":"unaffected","lessThanOrEqual":"4.19.*","versionType":"semver"},{"version":"5.4.241","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.178","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.107","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.24","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.2.11","status":"unaffected","lessThanOrEqual":"6.2.*","versionType":"semver"},{"version":"6.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nilfs2/segment.c"]}],"references":["https://git.kernel.org/stable/c/034cce77d52ba013ce62b4f5258c29907eb1ada5","https://git.kernel.org/stable/c/0dbf0e64b91ee8fcb278aea93eb06fc7d56ecbcc","https://git.kernel.org/stable/c/613bf23c070d11c525268f2945aa594704a9b764","https://git.kernel.org/stable/c/f32297dba338dc06d62286dedb3cdbd5175b1719","https://git.kernel.org/stable/c/92684e02654c91a61a0b0561433b710bcece19fe","https://git.kernel.org/stable/c/bae009a2f1b7c2011d2e92d8c84868d315c0b97e","https://git.kernel.org/stable/c/b4d80bd6370b81a1725b6b8f7894802c23a14e9f","https://git.kernel.org/stable/c/6be49d100c22ffea3287a4b19d7639d259888e33"],"weaknesses":[],"ingestedAt":"2026-10-29T20:06:33.064Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2023/53xxx/CVE-2023-53608.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2023-53608","state":"PUBLISHED","datePublished":"2025-10-04T15:44:17.302Z","dateUpdated":"2026-08-05T09:15:06.157Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-10-04T15:40:38.480Z"},"containers":{"cna":{"title":"nilfs2: fix potential UAF of struct nilfs_sc_info in nilfs_segctor_thread()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnilfs2: fix potential UAF of struct nilfs_sc_info in nilfs_segctor_thread()\n\nThe finalization of nilfs_segctor_thread() can race with\nnilfs_segctor_kill_thread() which terminates that thread, potentially\ncausing a use-after-free BUG as KASAN detected.\n\nAt the end of nilfs_segctor_thread(), it assigns NULL to \"sc_task\" member\nof \"struct nilfs_sc_info\" to indicate the thread has finished, and then\nnotifies nilfs_segctor_kill_thread() of this using waitqueue\n\"sc_wait_task\" on the struct nilfs_sc_info.\n\nHowever, here, immediately after the NULL assignment to \"sc_task\", it is\npossible that nilfs_segctor_kill_thread() will detect it and return to\ncontinue the deallocation, freeing the nilfs_sc_info structure before the\nthread does the notification.\n\nThis fixes the issue by protecting the NULL assignment to \"sc_task\" and\nits notification, with spinlock \"sc_state_lock\" of the struct\nnilfs_sc_info.  Since nilfs_segctor_kill_thread() does a final check to\nsee if \"sc_task\" is NULL with \"sc_state_lock\" locked, this can eliminate\nthe race."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453","status":"affected","lessThan":"034cce77d52ba013ce62b4f5258c29907eb1ada5","versionType":"git"},{"version":"9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453","status":"affected","lessThan":"0dbf0e64b91ee8fcb278aea93eb06fc7d56ecbcc","versionType":"git"},{"version":"9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453","status":"affected","lessThan":"613bf23c070d11c525268f2945aa594704a9b764","versionType":"git"},{"version":"9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453","status":"affected","lessThan":"f32297dba338dc06d62286dedb3cdbd5175b1719","versionType":"git"},{"version":"9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453","status":"affected","lessThan":"92684e02654c91a61a0b0561433b710bcece19fe","versionType":"git"},{"version":"9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453","status":"affected","lessThan":"bae009a2f1b7c2011d2e92d8c84868d315c0b97e","versionType":"git"},{"version":"9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453","status":"affected","lessThan":"b4d80bd6370b81a1725b6b8f7894802c23a14e9f","versionType":"git"},{"version":"9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453","status":"affected","lessThan":"6be49d100c22ffea3287a4b19d7639d259888e33","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nilfs2/segment.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.30","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.30","versionType":"semver"},{"version":"4.14.313","status":"unaffected","lessThanOrEqual":"4.14.*","versionType":"semver"},{"version":"4.19.281","status":"unaffected","lessThanOrEqual":"4.19.*","versionType":"semver"},{"version":"5.4.241","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.178","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.107","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.24","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.2.11","status":"unaffected","lessThanOrEqual":"6.2.*","versionType":"semver"},{"version":"6.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nilfs2/segment.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/034cce77d52ba013ce62b4f5258c29907eb1ada5"},{"url":"https://git.kernel.org/stable/c/0dbf0e64b91ee8fcb278aea93eb06fc7d56ecbcc"},{"url":"https://git.kernel.org/stable/c/613bf23c070d11c525268f2945aa594704a9b764"},{"url":"https://git.kernel.org/stable/c/f32297dba338dc06d62286dedb3cdbd5175b1719"},{"url":"https://git.kernel.org/stable/c/92684e02654c91a61a0b0561433b710bcece19fe"},{"url":"https://git.kernel.org/stable/c/bae009a2f1b7c2011d2e92d8c84868d315c0b97e"},{"url":"https://git.kernel.org/stable/c/b4d80bd6370b81a1725b6b8f7894802c23a14e9f"},{"url":"https://git.kernel.org/stable/c/6be49d100c22ffea3287a4b19d7639d259888e33"}],"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 race is only reachable through local filesystem operations — mount(2)/umount(2) of a nilfs2 volume (or the mount-time rollforward recovery attach/detach in nilfs_salvage_orphan_logs()). No network or peer-supplied data reaches nilfs_segctor_thread()/nilfs_segctor_kill_thread().\nAC:L - The attacker creates both sides of the race: the unmount/teardown request is what wakes the segctord kthread and drives it to end_thread, and the attempt can be repeated indefinitely via mount/unmount cycles (a recovery-requiring image makes even a plain mount start and kill the thread), with the preemption window widened by ordinary CPU contention.\nPR:L - An unprivileged local user reaches the teardown path on any ordinary desktop/kiosk through removable-media automount (udisks2/autofs mounts and unmounts a nilfs2 volume on the session user's behalf) or `user` fstab entries; no capability check is performed inside the racing code itself, consistent with other unmount-path filesystem teardown CVEs.\nUI:N - The attacker performs the mount/unmount cycling themselves; no separate victim has to open a file, run a command, or take any action for the race to be triggered.\nS:U - The use-after-free corrupts kernel heap memory within the same kernel security authority; no VM, IOMMU, container, or sandbox boundary is crossed.\nC:H - After kfree(sci) the kthread's wake_up() walks sci->sc_wait_task's list from the freed ~kmalloc-512 slot, so a reclaiming spray lets the attacker steer the traversal and the curr->func() indirect call, yielding kernel-memory disclosure; per UAF guidance this is High.\nI:H - wake_up() on the freed object performs a spinlock write into freed memory, list_del-style pointer writes on attacker-controlled list entries, and an indirect call through curr->func — a write and control-flow-hijack primitive exploitable for privilege escalation.\nA:H - The bug was reported by syzbot as a KASAN-detected use-after-free BUG; locking and dereferencing freed slab memory reliably produces an oops or panic even without successful exploitation."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T09:15:06.157Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.30","versionEndExcluding":"4.14.313"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.30","versionEndExcluding":"4.19.281"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.30","versionEndExcluding":"5.4.241"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.30","versionEndExcluding":"5.10.178"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.30","versionEndExcluding":"5.15.107"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.30","versionEndExcluding":"6.1.24"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.30","versionEndExcluding":"6.2.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.30","versionEndExcluding":"6.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}