4.9
MEDIUM CVSS 3.1
CVE-2026-10645
fs: ext2: Missing structural validation of directory entries can cause out-of-bounds read and zero-progress directory traversal
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.

INFO

Published Date :

June 22, 2026, 11:48 p.m.

Last Modified :

June 22, 2026, 11:48 p.m.

Remotely Exploit :

No

Source :

zephyr
Affected Products

The following products are affected by CVE-2026-10645 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 MEDIUM e2e69745-5e70-4e92-8431-deb5529a81ad
Solution
Validate directory entry structure and bounds before copying names and advancing traversal.
  • Validate de_rec_len and de_name_len against block boundaries.
  • Ensure de_rec_len is non-zero and sufficient for entry header.
  • Copy names only after validating entry structure.
  • Patch the ext2 directory-entry parser.

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EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.