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

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.

Problem type

Out-of-bounds Read

Affected products

zephyrproject-rtos

Zephyr

<= 4.4 - AFFECTED

References

github.com

https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-hwrh-9h3x-vccm

JSON source

https://cveawg.mitre.org/api/cve/CVE-2026-10645

Click to expand

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    "assignerShortName": "zephyr",
    "dateUpdated": "2026-06-22T23:48:11.747Z",
    "dateReserved": "2026-06-02T15:11:47.668Z",
    "datePublished": "2026-06-22T23:48:11.747Z",
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      "title": "fs: ext2: Missing structural validation of directory entries can cause out-of-bounds read and zero-progress directory traversal",
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