{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-109411", "assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749", "state": "PUBLISHED", "assignerShortName": "redhat", "dateReserved": "2026-10-12T15:19:07.605Z", "datePublished": "2026-10-28T19:17:45.459Z", "dateUpdated": "2026-10-28T19:17:45.459Z"}, "containers": {"cna": {"title": "Samba: access control bypass via vfs_ceph_rgw case-insensitive open", "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"}], "descriptions": [{"lang": "en", "value": "An access control bypass flaw was found 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", "versions": [{"status": "affected", "version": "4.25.0", "lessThan": "4.25.1", "versionType": "semver"}], "packageName": "samba", "collectionURL": "https://gitlab.com/samba-team/samba", "defaultStatus": "unaffected"}, {"vendor": "Red Hat", "product": "Red Hat Enterprise Linux 10", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "samba", "defaultStatus": "unaffected", "cpes": ["cpe:/o:redhat:enterprise_linux:10"]}, {"vendor": "Red Hat", "product": "Red Hat Enterprise Linux 6", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "samba", "defaultStatus": "unaffected", "cpes": ["cpe:/o:redhat:enterprise_linux:6"]}, {"vendor": "Red Hat", "product": "Red Hat Enterprise Linux 6", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "samba4", "defaultStatus": "unaffected", "cpes": ["cpe:/o:redhat:enterprise_linux:6"]}, {"vendor": "Red Hat", "product": "Red Hat Enterprise Linux 7", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "samba", "defaultStatus": "unaffected", "cpes": ["cpe:/o:redhat:enterprise_linux:7"]}, {"vendor": "Red Hat", "product": "Red Hat Enterprise Linux 8", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "samba", "defaultStatus": "unaffected", "cpes": ["cpe:/o:redhat:enterprise_linux:8"]}, {"vendor": "Red Hat", "product": "Red Hat Enterprise Linux 9", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "samba", "defaultStatus": "unaffected", "cpes": ["cpe:/o:redhat:enterprise_linux:9"]}, {"vendor": "Red Hat", "product": "Red Hat OpenShift Container Platform 4", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "openshift/ose-rhel-coreos-8", "defaultStatus": "unaffected", "cpes": ["cpe:/a:redhat:openshift:4"]}, {"vendor": "Red Hat", "product": "Red Hat OpenShift Container Platform 4", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "openshift/ose-rhel-coreos-9", "defaultStatus": "unaffected", "cpes": ["cpe:/a:redhat:openshift:4"]}], "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"}], "datePublic": "2026-10-23T15:00:00.000Z", "problemTypes": [{"descriptions": [{"cweId": "CWE-178", "description": "Improper Handling of Case Sensitivity", "lang": "en", "type": "CWE"}]}], "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."}], "providerMetadata": {"orgId": "53f830b8-0a3f-465b-8143-3b8a9948e749", "shortName": "redhat", "dateUpdated": "2026-10-28T19:17:45.459Z"}, "x_generator": {"engine": "cvelib 1.8.0"}}}}

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{"affected": [{"affectedData": [{"collectionURL": "https://gitlab.com/samba-team/samba", "defaultStatus": "unaffected", "packageName": "samba", "product": "Samba", "vendor": "Samba", "versions": [{"lessThan": "4.25.1", "status": "affected", "version": "4.25.0", "versionType": "semver"}]}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/o:redhat:enterprise_linux:10"], "defaultStatus": "unaffected", "packageName": "samba", "product": "Red Hat Enterprise Linux 10", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/o:redhat:enterprise_linux:6"], "defaultStatus": "unaffected", "packageName": "samba", "product": "Red Hat Enterprise Linux 6", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/o:redhat:enterprise_linux:6"], "defaultStatus": "unaffected", "packageName": "samba4", "product": "Red Hat Enterprise Linux 6", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/o:redhat:enterprise_linux:7"], "defaultStatus": "unaffected", "packageName": "samba", "product": "Red Hat Enterprise Linux 7", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/o:redhat:enterprise_linux:8"], "defaultStatus": "unaffected", "packageName": "samba", "product": "Red Hat Enterprise Linux 8", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/o:redhat:enterprise_linux:9"], "defaultStatus": "unaffected", "packageName": "samba", "product": "Red Hat Enterprise Linux 9", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:openshift:4"], "defaultStatus": "unaffected", "packageName": "openshift/ose-rhel-coreos-8", "product": "Red Hat OpenShift Container Platform 4", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:openshift:4"], "defaultStatus": "unaffected", "packageName": "openshift/ose-rhel-coreos-9", "product": "Red Hat OpenShift Container Platform 4", "vendor": "Red Hat"}], "source": "secalert@redhat.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "An access control bypass flaw was found 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."}], "id": "CVE-2026-109411", "lastModified": "2026-10-28T20:17:17.137", "metrics": {"cvssMetricV31": [{"cvssData": {"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"}, "exploitabilityScore": 2.8, "impactScore": 5.2, "source": "secalert@redhat.com", "type": "Primary"}]}, "published": "2026-10-28T20:17:17.007", "references": [{"source": "secalert@redhat.com", "url": "https://access.redhat.com/security/cve/CVE-2026-109411"}, {"source": "secalert@redhat.com", "url": "https://attachments.samba.org/attachment.cgi?id=19294"}, {"source": "secalert@redhat.com", "url": "https://attachments.samba.org/attachment.cgi?id=19295"}, {"source": "secalert@redhat.com", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2552136"}, {"source": "secalert@redhat.com", "url": "https://bugzilla.samba.org/show_bug.cgi?id=16276"}], "sourceIdentifier": "secalert@redhat.com", "vulnStatus": "Awaiting Analysis", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-178"}], "source": "secalert@redhat.com", "type": "Primary"}]}

{"acknowledgement": "Red Hat would like to thank hataehoon for reporting this issue.", "bugzilla": {"description": "samba: Access control bypass via vfs_ceph_rgw case-insensitive open", "id": "2552136", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2552136"}, "csaw": false, "cvss3": {"cvss3_base_score": "8.1", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N", "status": "draft"}, "cwe": "CWE-178", "details": ["An access control bypass flaw was found 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."], "mitigation": {"lang": "en:us", "value": "Only shares configured with the vfs_ceph_rgw module are affected.\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```\nsystemctl reload smb\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.\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. \nNote: This changes share behavior for clients that rely on case-insensitive name handling."}, "name": "CVE-2026-109411", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Not affected", "package_name": "samba", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "samba", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "samba4", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "samba", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "samba", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "samba", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Not affected", "package_name": "openshift/ose-rhel-coreos-8", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Not affected", "package_name": "openshift/ose-rhel-coreos-9", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-10-23T15:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-109411\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-109411\nhttps://attachments.samba.org/attachment.cgi?id=19294\nhttps://attachments.samba.org/attachment.cgi?id=19295\nhttps://bugzilla.samba.org/show_bug.cgi?id=16276"], "statement": "This vulnerability is strictly limited to Samba deployments utilizing the experimental S3-to-SMB gateway feature (vfs_ceph_rgw).\nThis specific feature was introduced in upstream Samba version 4.25.\nStandard Red Hat Enterprise Linux (RHEL), Red Hat Ceph Storage, Red Hat In-Vehicle OS (RHIVOS), and OpenShift Container Platform packages do not include or support this experimental module. The Samba versions shipped by Red Hat predate the introduction of this feature; therefore, the vulnerable code is not present.\n**Clarification for Red Hat Ceph Storage Users:**\nPlease distinguish between the standard CephFS integration and the vulnerable component:\n**Safe (vfs_ceph):** Red Hat Ceph Storage utilizes the native vfs_ceph module for CephFS integration. This module interacts directly with libcephfs to enforce standard POSIX ACLs. It is architecturally distinct and is not related to this issue.\n**Vulnerable (vfs_ceph_rgw):** The vulnerability exists solely in this separate, experimental vfs_ceph_rgw module (used for mapping S3 buckets to SMB) and as said above, this module is not present in Red Hat distributed Samba packages.", "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": null}], "enrichment": {"confidence": 80.0, "confidence_source": "inferred", "scores": [{"score": 80.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "product": "samba", "vendor": "samba"}], "created": "2026-10-26T13:30:08.852033+00:00", "updated": "2026-10-26T14:45:12.407401+00:00", "vendors": ["samba", "samba$PRODUCT$samba"]}