CVE-2026-64397

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Concurrent QUERY_DIRECTORY requests using the\nsame file handle can overwrite this pointer while an iterate_dir() callback\nis still using it, resulting in a stack use-after-free.\n\nAdd a per-file mutex and hold it while accessing the shared directory\nenumeration state. The lock covers scan restart, dot entry state,\nreaddir_data setup and iteration, and response construction. This prevents\nanother request from replacing readdir_data.private before the current\nrequest has finished using it and also serializes the shared file position."}], "metrics": [{"cvssV3_1": {"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"}, "scenarios": [{"lang": "en", "value": "AV:N - KSMBD processes attacker-supplied SMB2 QUERY_DIRECTORY requests over TCP port 445, so the vulnerable callback is remotely reachable.\nAC:L - The attacker controls both concurrent requests using the same directory handle and can prolong one enumeration while rapidly completing the other, making the race repeatable.\nPR:N - Although a valid session, tree connection, and readable directory handle are required, ksmbd supports passwordless guest sessions; a guest-readable share therefore permits exploitation without pre-existing privileges.\nUI:N - No victim action is required after the SMB server and accessible share are available.\nS:U - Exploitation compromises the kernel hosting the SMB server without crossing a separate virtualization, sandbox, or IOMMU security authority.\nC:H - The stack use-after-free exposes stale stack, work, search-pattern, and response-buffer pointers, providing a defensible path to high-impact kernel memory disclosure.\nI:H - The callback writes attacker-influenced directory-entry data through a stale d_info pointer and modifies reclaimed stack or response-buffer memory, potentially enabling arbitrary corruption and code execution.\nA:H - Dereferencing or writing through the freed stack and associated stale heap pointers can cause a kernel oops or panic, and the attacker can trigger the race repeatedly over the network."}]}], "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", "fs/smb/server/vfs_cache.c", "fs/smb/server/vfs_cache.h"], "versions": [{"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9", "lessThan": "1426fd79102539bc0ab5c8fced047ad4313b9908", "status": "affected", "versionType": "git"}, {"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9", "lessThan": "2a64dbf9c739ddf7a25a066507597bf89f8f73d2", "status": "affected", "versionType": "git"}, {"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9", "lessThan": "64dac2d486ec1eb18dc00968b16a230b6b75ec24", "status": "affected", "versionType": "git"}, {"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9", "lessThan": "a1d5d31cad593ea5e1b637f2f39c9ef6d09d1199", "status": "affected", "versionType": "git"}, {"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9", "lessThan": "fd22b039a5a05bc1d6818e9dcd1001fb432a829d", "status": "affected", "versionType": "git"}, {"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9", "lessThan": "be6d26bf27499977c746abc163659915082348d8", "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", "fs/smb/server/vfs_cache.c", "fs/smb/server/vfs_cache.h"], "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/1426fd79102539bc0ab5c8fced047ad4313b9908"}, {"url": "https://git.kernel.org/stable/c/2a64dbf9c739ddf7a25a066507597bf89f8f73d2"}, {"url": "https://git.kernel.org/stable/c/64dac2d486ec1eb18dc00968b16a230b6b75ec24"}, {"url": "https://git.kernel.org/stable/c/a1d5d31cad593ea5e1b637f2f39c9ef6d09d1199"}, {"url": "https://git.kernel.org/stable/c/fd22b039a5a05bc1d6818e9dcd1001fb432a829d"}, {"url": "https://git.kernel.org/stable/c/be6d26bf27499977c746abc163659915082348d8"}], "title": "ksmbd: serialize QUERY_DIRECTORY requests per file", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

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Concurrent QUERY_DIRECTORY requests using the\nsame file handle can overwrite this pointer while an iterate_dir() callback\nis still using it, resulting in a stack use-after-free.\n\nAdd a per-file mutex and hold it while accessing the shared directory\nenumeration state. The lock covers scan restart, dot entry state,\nreaddir_data setup and iteration, and response construction. This prevents\nanother request from replacing readdir_data.private before the current\nrequest has finished using it and also serializes the shared file position."}], "id": "CVE-2026-64397", "lastModified": "2026-09-04T14:47:10.993", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.8, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-07-25T10:17:23.160", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/1426fd79102539bc0ab5c8fced047ad4313b9908"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/2a64dbf9c739ddf7a25a066507597bf89f8f73d2"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/64dac2d486ec1eb18dc00968b16a230b6b75ec24"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/a1d5d31cad593ea5e1b637f2f39c9ef6d09d1199"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/be6d26bf27499977c746abc163659915082348d8"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/fd22b039a5a05bc1d6818e9dcd1001fb432a829d"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-416"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"bugzilla": {"description": "kernel: ksmbd: serialize QUERY_DIRECTORY requests per file", "id": "2507300", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2507300"}, "csaw": false, "cwe": "CWE-562", "details": ["A flaw was found in the Linux kernel's ksmbd (kernel Server Message Block daemon) component. Concurrent directory query requests using the same file handle can lead to a stack use-after-free vulnerability. This occurs because smb2_query_dir() stores a pointer to stack-allocated data that can be overwritten by another request while still in use. An attacker could exploit this to cause a denial of service."], "name": "CVE-2026-64397", "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": "important", "package_name": "erlang27", "product_name": "Red Hat Hardened Images"}], "public_date": "2026-07-25T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-64397\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-64397\nhttps://lore.kernel.org/linux-cve-announce/2026072529-CVE-2026-64397-7e0d@gregkh/T"]}

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