CVE-2026-64257

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However, the overlap\nhandling in __smb2_calc_size() clears data_length, which can make an\ninvalid response appear to have no data area and so qualify for the\nexception.\n\nTrack data area overlap separately and reject such responses before\napplying the length compatibility exceptions."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H", "baseScore": 9.1, "baseSeverity": "CRITICAL"}, "scenarios": [{"lang": "en", "value": "AV:N - A malicious or compromised SMB server can deliver the crafted SMB2 response over TCP during client negotiation.\nAC:L - The overlapping offset and oversized length are attacker-controlled and deterministically bypass validation; no race or uncontrolled memory layout is required to trigger the out-of-bounds read.\nPR:N - The vulnerable NEGOTIATE response is processed before SMB authentication or signature verification, requiring no privileges or credentials on the target.\nUI:N - An already configured SMB mount can negotiate during automatic mounting or reconnection without a human opening crafted content.\nS:U - The vulnerable parser and the affected kernel memory remain within the Linux kernel's security authority.\nC:H - The validation mismatch permits an attacker-controlled ASN.1 length to read far beyond the 448-byte receive object, potentially traversing tens of kilobytes of adjacent kernel memory.\nI:N - The investigated paths provide an out-of-bounds read but no out-of-bounds write, use-after-free, type confusion, or other arbitrary modification primitive.\nA:H - The slab out-of-bounds access is repeatable and can produce a kernel fault or panic, particularly on hardened or memory-safety-instrumented deployments."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/smb/client/smb2misc.c"], "versions": [{"version": "31c6312608c60b72a1feb99a5afb680645a3e8a3", "lessThan": "445ece263131780dee273d727a4d6f11934feec7", "status": "affected", "versionType": "git"}, {"version": "573e502d14714d2947e22e7eff40ec20a6a44a42", "lessThan": "36bfa52459e45c0d5b668de2f1c91f6dc5c67775", "status": "affected", "versionType": "git"}, {"version": "419ec1b604d7fb60c10aec2dc062371f9fcd4940", "lessThan": "4a9d2657d3e05f6ed09c148cb127b4e58702275f", "status": "affected", "versionType": "git"}, {"version": "ceb875a375dedbf51c9425c1d13a2d7a8435c08c", "lessThan": "fdafa1e68dc75045b7b617e6e7d2854950804d83", "status": "affected", "versionType": "git"}, {"version": "6e9d10f62773b99bd927940fd9cbdfe7207e23ff", "lessThan": "57cba95f0e97c6f6e45e6731da30aff091bd7460", "status": "affected", "versionType": "git"}, {"version": "53b7c271f06be4dd5cfc8c6ef552a8355c891a7f", "lessThan": "8986c932905ea508d66da421eb2eb6e676ace1fe", "status": "affected", "versionType": "git"}, {"version": "8d0bbc78046d264bbf6a574ea6f9072258a43e35", "status": "affected", "versionType": "git"}, {"version": "b6a381c01e2ac98a48e32ac0f2a45bbadd9e26b0", "status": "affected", "versionType": "git"}, {"version": "5.10.261", "lessThan": "5.11", "status": "affected", "versionType": "semver"}, {"version": "5.15.212", "lessThan": "5.16", "status": "affected", "versionType": "semver"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/smb/client/smb2misc.c"]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10.261"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15.212"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/445ece263131780dee273d727a4d6f11934feec7"}, {"url": "https://git.kernel.org/stable/c/36bfa52459e45c0d5b668de2f1c91f6dc5c67775"}, {"url": "https://git.kernel.org/stable/c/4a9d2657d3e05f6ed09c148cb127b4e58702275f"}, {"url": "https://git.kernel.org/stable/c/fdafa1e68dc75045b7b617e6e7d2854950804d83"}, {"url": "https://git.kernel.org/stable/c/57cba95f0e97c6f6e45e6731da30aff091bd7460"}, {"url": "https://git.kernel.org/stable/c/8986c932905ea508d66da421eb2eb6e676ace1fe"}], "title": "smb: client: reject overlapping data areas in SMB2 responses", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

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{"bugzilla": {"description": "kernel: smb: client: reject overlapping data areas in SMB2 responses", "id": "2507166", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2507166"}, "csaw": false, "cwe": "CWE-130", "details": ["A flaw was found in the Linux kernel's Server Message Block (SMB) client. A remote attacker could exploit a vulnerability where the client improperly handles SMB2 responses containing overlapping data areas. This incorrect processing of malformed network data could lead to a denial of service (DoS) or other severe system impact, compromising the availability and potentially the confidentiality of the affected system."], "name": "CVE-2026-64257", "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"}], "public_date": "2026-07-25T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-64257\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-64257\nhttps://lore.kernel.org/linux-cve-announce/2026072556-CVE-2026-64257-cdc9@gregkh/T"]}

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