{"id":"CVE-2026-109411","state":"PUBLISHED","title":"Samba: access control bypass via vfs_ceph_rgw case-insensitive open","description":"An access control bypass flaw was identified in Samba's vfs_ceph_rgw module in it's openat() function. An authenticated user can bypass access controls to read or overwrite restricted files on shares configured with the experimental vfs_ceph_rgw module. When a client requests an existing file using mismatched character casing, the module fails to perform a case-insensitive lookup correctly, causing the server to treat the operation as creating a new file. As a result, the server skips standard permission checks on the existing file, allowing the attacker to access or overwrite sensitive data owned by other users.","publishedAt":"2026-10-28T19:17:45.459Z","updatedAt":"2026-10-30T05:04:35.990Z","severity":{"score":8.1,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N","source":"redhat"},"assigner":"redhat","products":["Samba Samba","Red Hat Red Hat Enterprise Linux 10","Red Hat Red Hat Enterprise Linux 6","Red Hat Red Hat Enterprise Linux 7","Red Hat Red Hat Enterprise Linux 8","Red Hat Red Hat Enterprise Linux 9","Red Hat Red Hat OpenShift Container Platform 4","Red Hat Red Hat OpenShift Container Platform 5"],"affected":[{"vendor":"Samba","product":"Samba","packageName":"samba","defaultStatus":"unaffected","versions":[{"version":"4.25.0","status":"affected","lessThan":"4.25.1","versionType":"semver"}],"collectionURL":"https://gitlab.com/samba-team/samba"},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 10","packageName":"samba","defaultStatus":"unaffected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:10"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 6","packageName":"samba","defaultStatus":"unaffected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:6"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 6","packageName":"samba4","defaultStatus":"unaffected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:6"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 7","packageName":"samba","defaultStatus":"unaffected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:7"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 8","packageName":"samba","defaultStatus":"unaffected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:8"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 9","packageName":"samba","defaultStatus":"unaffected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:9"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 4","packageName":"openshift/ose-rhel-coreos-8","defaultStatus":"unaffected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:openshift:4"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 4","packageName":"openshift/ose-rhel-coreos-9","defaultStatus":"unaffected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:openshift:4"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 5","packageName":"openshift/ose-rhel-coreos-9","defaultStatus":"unaffected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:openshift:5"]}],"references":["https://access.redhat.com/security/cve/CVE-2026-109411","https://attachments.samba.org/attachment.cgi?id=19294","https://attachments.samba.org/attachment.cgi?id=19295","https://bugzilla.redhat.com/show_bug.cgi?id=2552136","https://bugzilla.samba.org/show_bug.cgi?id=16276"],"weaknesses":["CWE-178"],"ingestedAt":"2026-10-30T05:20:06.850Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/109xxx/CVE-2026-109411.json","commit":"cc648b769ef35555df626cb69f86fccdf0d85f6a","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-109411","state":"PUBLISHED","datePublished":"2026-10-28T19:17:45.459Z","dateUpdated":"2026-10-30T05:04:35.990Z","assignerShortName":"redhat","assignerOrgId":"53f830b8-0a3f-465b-8143-3b8a9948e749","dateReserved":"2026-10-12T15:19:07.605Z"},"containers":{"cna":{"title":"Samba: access control bypass via vfs_ceph_rgw case-insensitive open","descriptions":[{"lang":"en","value":"An access control bypass flaw was identified in Samba's vfs_ceph_rgw module in it's openat() function. An authenticated user can bypass access controls to read or overwrite restricted files on shares configured with the experimental vfs_ceph_rgw module. When a client requests an existing file using mismatched character casing, the module fails to perform a case-insensitive lookup correctly, causing the server to treat the operation as creating a new file. As a result, the server skips standard permission checks on the existing file, allowing the attacker to access or overwrite sensitive data owned by other users."}],"affected":[{"vendor":"Samba","product":"Samba","packageName":"samba","defaultStatus":"unaffected","versions":[{"version":"4.25.0","status":"affected","lessThan":"4.25.1","versionType":"semver"}],"collectionURL":"https://gitlab.com/samba-team/samba"},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 10","packageName":"samba","defaultStatus":"unaffected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:10"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 6","packageName":"samba","defaultStatus":"unaffected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:6"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 6","packageName":"samba4","defaultStatus":"unaffected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:6"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 7","packageName":"samba","defaultStatus":"unaffected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:7"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 8","packageName":"samba","defaultStatus":"unaffected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:8"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 9","packageName":"samba","defaultStatus":"unaffected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:9"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 4","packageName":"openshift/ose-rhel-coreos-8","defaultStatus":"unaffected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:openshift:4"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 4","packageName":"openshift/ose-rhel-coreos-9","defaultStatus":"unaffected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:openshift:4"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 5","packageName":"openshift/ose-rhel-coreos-9","defaultStatus":"unaffected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:openshift:5"]}],"references":[{"url":"https://access.redhat.com/security/cve/CVE-2026-109411","tags":["vdb-entry","x_refsource_REDHAT"]},{"url":"https://attachments.samba.org/attachment.cgi?id=19294"},{"url":"https://attachments.samba.org/attachment.cgi?id=19295"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2552136","name":"RHBZ#2552136","tags":["issue-tracking","x_refsource_REDHAT"]},{"url":"https://bugzilla.samba.org/show_bug.cgi?id=16276"}],"metrics":[{"other":{"content":{"value":"Important","namespace":"https://access.redhat.com/security/updates/classification/"},"type":"Red Hat severity rating"}},{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":8.1,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N","version":"3.1"},"format":"CVSS"}],"problemTypes":[{"descriptions":[{"cweId":"CWE-178","description":"Improper Handling of Case Sensitivity","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"redhat","orgId":"53f830b8-0a3f-465b-8143-3b8a9948e749","dateUpdated":"2026-10-30T05:04:35.990Z"},"datePublic":"2026-10-23T15:00:00.000Z","x_redhatCweChain":"CWE-178: Improper Handling of Case Sensitivity","workarounds":[{"lang":"en","value":"Only shares configured with the vfs_ceph_rgw module are affected.\n\nTo mitigate this vulnerability, disable the experimental `vfs_ceph_rgw` module on any configured Samba shares. Edit `/etc/samba/smb.conf` to remove `ceph_rgw` from the `vfs objects` setting under the relevant share sections, then reload the Samba service:\n\n```\nsystemctl reload smb\n```\n\nWarning: Reloading or restarting the `smb` service may briefly interrupt active client sessions. Additionally, removing this module disables Ceph RGW integration for the affected shares.\n\nSetting ```case sensitive = yes``` on affected shares avoids the vulnerability, because the differently-cased name is then treated as a distinct object rather than resolving to the existing file. \n\nNote: This changes share behavior for clients that rely on case-insensitive name handling."}],"timeline":[{"lang":"en","time":"2026-10-14T00:00:00.000Z","value":"Reported to Red Hat."},{"lang":"en","time":"2026-10-23T15:00:00.000Z","value":"Made public."}],"credits":[{"lang":"en","value":"Red Hat would like to thank hataehoon for reporting this issue."}],"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-29T15:36:56.528765Z","id":"CVE-2026-109411","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-29T20:54:00.468Z"}}]}}}