ksmbd: fix out-of-bounds write in smb2_get_ea() EA alignment_CVE-2026-31705

{
    "lastseen": "",
    "description": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix out-of-bounds write in smb2_get_ea() EA alignment\n\nsmb2_get_ea() applies 4-byte alignment padding via memset() after\nwriting each EA entry. The bounds check on buf_free_len is performed\nbefore the value memcpy, but the alignment memset fires unconditionally\nafterward with no check on remaining space.\n\nWhen the EA value exactly fills the remaining buffer (buf_free_len == 0\nafter value subtraction), the alignment memset writes 1-3 NUL bytes\npast the buf_free_len boundary. In compound requests where the response\nbuffer is shared across commands, the first command (e.g., READ) can\nconsume most of the buffer, leaving a tight remainder for the QUERY_INFO\nEA response. The alignment memset then overwrites past the physical\nkvmalloc allocation into adjacent kernel heap memory.\n\nAdd a bounds check before the alignment memset to ensure buf_free_len\ncan accommodate the padding bytes.\n\nThis is the same bug pattern fixed by commit beef2634f81f (\"ksmbd: fix\npotencial OOB in get_file_all_info() for compound requests\") and\ncommit fda9522ed6af (\"ksmbd: fix OOB write in QUERY_INFO for compound\nrequests\"), both of which added bounds checks before unconditional\nwrites in QUERY_INFO response handlers.",
    "published": "2026-05-01T13:56:03.896Z",
    "modified": "2026-05-03T05:45:28.481Z",
    "type": "cve",
    "title": "ksmbd: fix out-of-bounds write in smb2_get_ea() EA alignment",
    "source": "Linux",
    "references": "https://git.kernel.org/stable/c/ffbce350c6fd1e99116ea57383b9031717e36d3b\nhttps://git.kernel.org/stable/c/98f3de6ef4efbd899348d333f0902dc4ff14380c\nhttps://git.kernel.org/stable/c/790304c02bf9bd7b8171feda4294d6e62d32ae8f\nhttps://git.kernel.org/stable/c/922d48fe8c19f388ffa2f709f33acaae4e408de2\nhttps://git.kernel.org/stable/c/30010c952077a1c89ecdd71fc4d574c75a8f5617",
    "id": "CVE-2026-31705",
    "bulletinFamily": "",
    "cwe": null,
    "cvelist": null,
    "sourceData": "Linux Linux e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d\nLinux Linux e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d\nLinux Linux e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d\nLinux Linux e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d\nLinux Linux e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d\nLinux Linux f2283680a80571ca82d710bc6ecd8f8beac67d63\nLinux Linux 9f297df20d93411c0b4ddad7f88ba04a7cd36e77\nLinux Linux 6.6",
    "sourceHref": "",
    "cvss": {
        "score": 9.8,
        "severity": "CRITICAL",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
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            "baseScore": 0,
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            "privilegesRequired": "",
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        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Linux",
    "version": "e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d",
    "vendor": "Linux",
    "ai_description": "Out-of-bounds write in smb2_get_ea() EA alignment in ksmbd",
    "ai_severity": "Critical",
    "ai_vendor": "Linux",
    "ai_product": "ksmbd",
    "ai_version": "e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d",
    "ai_score": 9.8
}