CVE-2026-64393

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This also removes the separate security information\ncredential setup and keeps all SET_INFO classes under one credential scope.\n\nDirect override_creds() is used because it can nest with the request\ncredential overrides already used by rename and link helpers."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H", "baseScore": 9.1, "baseSeverity": "CRITICAL"}, "scenarios": [{"lang": "en", "value": "AV:N - The vulnerable SMB2 SET_INFO handler is remotely reachable through ksmbd over TCP/445 or SMB Direct.\nAC:L - An attacker can deterministically open a handle and send a crafted SET_INFO request; no race or condition outside the attacker\u2019s control is required.\nPR:N - Although a valid SMB session, writable tree, and suitable handle are required, ksmbd supports passwordless guest sessions on writable shares, making exploitation possible without attacker privileges in a reasonable deployment.\nUI:N - The attacker directly opens the handle and submits the SET_INFO request without any victim action.\nS:U - The bypass affects files and services governed by the same host kernel and filesystem security authority, without crossing a virtualization or sandbox boundary.\nC:N - The flaw provides unauthorized mutation through metadata, xattr, and truncation operations but does not itself disclose file contents or kernel memory.\nI:H - Privileged worker credentials can bypass opener UID, group, capability, inode, and LSM checks, permitting protected metadata changes and destructive truncation of an affected file.\nA:H - Repeated SET_INFO requests can truncate critical files or corrupt security-relevant metadata and xattrs, potentially disabling dependent services or exhausting filesystem resources."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/smb/server/smb2pdu.c"], "versions": [{"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9", "lessThan": "5cbabf3a71575cd31bc7785d92d4ab42338a654b", "status": "affected", "versionType": "git"}, {"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9", "lessThan": "b35afd5cf8fab236ef21117e42ee45691d4ffa7b", "status": "affected", "versionType": "git"}, {"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9", "lessThan": "0ce682867fd506f61f40c76bde7e4205bde34e87", "status": "affected", "versionType": "git"}, {"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9", "lessThan": "20ee516a62989a8d505ee432f9e59525ea23984e", "status": "affected", "versionType": "git"}, {"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9", "lessThan": "8cc9ec711f5255167247a9ab6a7179b787426ed7", "status": "affected", "versionType": "git"}, {"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9", "lessThan": "b383bcad3d2fe634b26efbce53e22bbb5753a520", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/smb/server/smb2pdu.c"], "versions": [{"version": "5.15", "status": "affected"}, {"version": "0", "lessThan": "5.15", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.178", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.96", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.39", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.4", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.1.178"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.6.145"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.12.96"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.18.39"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "7.1.4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "7.2"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/5cbabf3a71575cd31bc7785d92d4ab42338a654b"}, {"url": "https://git.kernel.org/stable/c/b35afd5cf8fab236ef21117e42ee45691d4ffa7b"}, {"url": "https://git.kernel.org/stable/c/0ce682867fd506f61f40c76bde7e4205bde34e87"}, {"url": "https://git.kernel.org/stable/c/20ee516a62989a8d505ee432f9e59525ea23984e"}, {"url": "https://git.kernel.org/stable/c/8cc9ec711f5255167247a9ab6a7179b787426ed7"}, {"url": "https://git.kernel.org/stable/c/b383bcad3d2fe634b26efbce53e22bbb5753a520"}], "title": "ksmbd: run set info with opener credentials", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

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Those helpers perform their owner,\ninode permission and LSM checks using the current ksmbd worker credentials.\n\nRun the complete SET_INFO dispatch with the credentials captured when the\nhandle was opened. This also removes the separate security information\ncredential setup and keeps all SET_INFO classes under one credential scope.\n\nDirect override_creds() is used because it can nest with the request\ncredential overrides already used by rename and link helpers."}], "id": "CVE-2026-64393", "lastModified": "2026-09-04T19:08:35.457", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.1, "baseSeverity": "CRITICAL", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.2, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-07-25T10:17:22.663", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/0ce682867fd506f61f40c76bde7e4205bde34e87"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/20ee516a62989a8d505ee432f9e59525ea23984e"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/5cbabf3a71575cd31bc7785d92d4ab42338a654b"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/8cc9ec711f5255167247a9ab6a7179b787426ed7"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/b35afd5cf8fab236ef21117e42ee45691d4ffa7b"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/b383bcad3d2fe634b26efbce53e22bbb5753a520"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "NVD-CWE-noinfo"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"bugzilla": {"description": "kernel: ksmbd: run set info with opener credentials", "id": "2507270", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2507270"}, "csaw": false, "cwe": "CWE-270", "details": ["A flaw was found in the Linux kernel's ksmbd component. This vulnerability allows a local attacker to escalate privileges by manipulating Server Message Block (SMB2) SET_INFO operations. The system incorrectly uses the ksmbd worker's credentials instead of the original user's credentials when performing file system checks, potentially bypassing security restrictions and enabling unauthorized actions."], "name": "CVE-2026-64393", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:hummingbird:1", "fix_state": "Not affected", "impact": "moderate", "package_name": "erlang27", "product_name": "Red Hat Hardened Images"}], "public_date": "2026-07-25T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-64393\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-64393\nhttps://lore.kernel.org/linux-cve-announce/2026072528-CVE-2026-64393-200f@gregkh/T"]}

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