{"api_version":"1","generated_at":"2026-10-29T14:00:36+00:00","cve":"CVE-2023-53867","urls":{"html":"https://cve.report/CVE-2023-53867","api":"https://cve.report/api/cve/CVE-2023-53867.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2023-53867","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2023-53867"},"summary":{"title":"ceph: fix potential use-after-free bug when trimming caps","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nceph: fix potential use-after-free bug when trimming caps\n\nWhen trimming the caps and just after the 'session->s_cap_lock' is\nreleased in ceph_iterate_session_caps() the cap maybe removed by\nanother thread, and when using the stale cap memory in the callbacks\nit will trigger use-after-free crash.\n\nWe need to check the existence of the cap just after the 'ci->i_ceph_lock'\nbeing acquired. 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22:17:50"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"9.8","severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"9.8","severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":9.8,"baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/2b2515b8095cf2149bef44383a99d5b5677f1831","name":"https://git.kernel.org/stable/c/2b2515b8095cf2149bef44383a99d5b5677f1831","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/ae6e935618d99cdba11eab4714092e7e5f13cf7e","name":"https://git.kernel.org/stable/c/ae6e935618d99cdba11eab4714092e7e5f13cf7e","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/aaf67de78807c59c35bafb5003d4fb457c764800","name":"https://git.kernel.org/stable/c/aaf67de78807c59c35bafb5003d4fb457c764800","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/448875a73e16ba7d81dec9274ce9d33a12d092fb","name":"https://git.kernel.org/stable/c/448875a73e16ba7d81dec9274ce9d33a12d092fb","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2023-53867","name":"CVE 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the Linux kernel, the following vulnerability has been resolved:\n\nceph: fix potential use-after-free bug when trimming caps\n\nWhen trimming the caps and just after the 'session->s_cap_lock' is\nreleased in ceph_iterate_session_caps() the cap maybe removed by\nanother thread, and when using the stale cap memory in the callbacks\nit will trigger use-after-free crash.\n\nWe need to check the existence of the cap just after the 'ci->i_ceph_lock'\nbeing acquired. 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The window spans sleeping operations (`d_find_primary()`, `ceph_mdsc_build_path()`, dentry pruning) and can be retried indefinitely, so it is reliably hit.\nPR:N - No credentials or privileges on the victim client are required — the malicious MDS peer needs no local authority, and the code runs unauthenticated with respect to the client's privilege model. Locally, mere unprivileged access to a mounted CephFS is enough to generate the concurrent cap churn.\nUI:N - Exploitation needs no victim action beyond an already-mounted CephFS, which is the normal operating state of an affected system; the MDS drives the whole sequence on its own.\nS:U - The stale `struct ceph_cap` corruption and the resulting oops are confined to the kernel's own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The use-after-free gives a read primitive over freed/recycled `ceph_cap` slab memory, and `reconnect_caps_cb()` encodes those stale fields (`cap->cap_id`, `cap->issued`) directly into the reconnect message transmitted to the MDS, exfiltrating freed-object contents to the attacker.\nI:H - The callbacks write into the stale object — `cap->seq/issue_seq/mseq/cap_gen = 0` in `reconnect_caps_cb()` and `cap->issued = cap->implemented = CEPH_CAP_PIN` in `wake_up_session_cb()` — corrupting a recycled `ceph_cap` (and thus another inode's capability/coherency state), a UAF write primitive usable for heap grooming toward control-flow hijack.\nA:H - The reported real-world outcome is a kernel NULL-pointer dereference oops in `__ceph_remove_cap()` from the trim-caps path (Ceph tracker #43272), and any use-after-free of the cap object crashes the client; the MDS can trigger it repeatedly."}]}],"providerMetadata":{"dateUpdated":"2026-08-05T09:16:28.667Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/2b2515b8095cf2149bef44383a99d5b5677f1831"},{"url":"https://git.kernel.org/stable/c/448875a73e16ba7d81dec9274ce9d33a12d092fb"},{"url":"https://git.kernel.org/stable/c/ae6e935618d99cdba11eab4714092e7e5f13cf7e"},{"url":"https://git.kernel.org/stable/c/aaf67de78807c59c35bafb5003d4fb457c764800"}],"title":"ceph: fix potential use-after-free bug when trimming caps","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2023-53867","datePublished":"2025-12-24T10:55:25.430Z","dateReserved":"2025-12-09T01:27:17.829Z","dateUpdated":"2026-10-15T21:41:37.567Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2025-12-24 11:15:51","lastModifiedDate":"2026-10-15 22:17:50","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":3.9,"impactScore":5.9}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-10-15T21:37:43.826196Z","id":"CVE-2023-53867","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2023","CveId":"53867","Ordinal":"1","Title":"ceph: fix potential use-after-free bug when trimming caps","CVE":"CVE-2023-53867","Year":"2023"},"notes":[{"CveYear":"2023","CveId":"53867","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nceph: fix potential use-after-free bug when trimming caps\n\nWhen trimming the caps and just after the 'session->s_cap_lock' is\nreleased in ceph_iterate_session_caps() the cap maybe removed by\nanother thread, and when using the stale cap memory in the callbacks\nit will trigger use-after-free crash.\n\nWe need to check the existence of the cap just after the 'ci->i_ceph_lock'\nbeing acquired. And do nothing if it's already removed.","Type":"Description","Title":"ceph: fix potential use-after-free bug when trimming caps"}]}}}