CVE-2026-10645 PUBLISHED

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

Assigner: zephyr
Reserved: 02.06.2026 Published: 22.06.2026 Updated: 23.06.2026

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.

Metrics

CVSS Vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H
CVSS Score: 4.9

Product Status

Vendor zephyrproject-rtos
Product Zephyr
Versions Default: unaffected
  • affected from * to 4.4 (incl.)

References

Problem Types

  • Out-of-bounds Read CWE