fs: ext2: Missing structural validation of directory entries can cause out-of-bounds read and zero-progress directory traversal_CVE-2026-10645

{
    "lastseen": "",
    "description": "Zephyr's ext2 directory-entry parser does not fully validate on-disk directory entry structure before copying the entry name and advancing traversal state. In ext2_fetch_direntry() (subsys/fs/ext2/ext2_diskops.c), the code only checks de_name_len <= EXT2_MAX_FILE_NAME and then copies the name with memcpy without validating the structural relationship between de_rec_len, de_name_len, and the directory block boundary (for example that de_rec_len is non-zero, at least the size of the entry header, and that the record fits within the block). Callers such as find_dir_entry() and ext2_get_direntry() (subsys/fs/ext2/ext2_impl.c) then advance traversal using the unvalidated de_rec_len. A crafted ext2 image can therefore cause an out-of-bounds read from the directory block buffer when a malformed entry near the end of a block triggers an oversized name copy, or a zero-progress infinite loop when de_rec_len == 0. The issue is not reached at mount time but later through directory traversal paths such as pathname lookup, stat/open/unlink/rename, and readdir. The primary impact is denial of service and out-of-bounds reads under attacker-controlled ext2 images mounted from untrusted media.",
    "published": "2026-06-22T23:48:11.747Z",
    "modified": "2026-06-22T23:48:11.747Z",
    "type": "cve",
    "title": "fs: ext2: Missing structural validation of directory entries can cause out-of-bounds read and zero-progress directory traversal",
    "source": "zephyr",
    "references": "https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-hwrh-9h3x-vccm",
    "id": "CVE-2026-10645",
    "bulletinFamily": "",
    "cwe": [
        "CWE-125"
    ],
    "cvelist": null,
    "sourceData": "zephyrproject-rtos Zephyr *",
    "sourceHref": "",
    "cvss": {
        "score": 4.9,
        "severity": "MEDIUM",
        "vector": "CVSS:3.1/AV:P/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
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        "baseScore": 0,
        "baseSeverity": "",
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        "privilegesRequired": "",
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        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
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            "baseScore": 0,
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        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Zephyr",
    "version": "*",
    "vendor": "zephyrproject-rtos",
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}