zephyrproject-rtos Zephyr up to 4.4 ext2_diskops.c ext2_fetch_direntry out-of-bounds

Summaryinfo

A vulnerability marked as problematic has been reported in zephyrproject-rtos Zephyr up to 4.4. Affected by this vulnerability is the function ext2_fetch_direntry of the file subsys/fs/ext2/ext2_diskops.c. The manipulation leads to out-of-bounds. This vulnerability is referenced as CVE-2026-10645. It is possible to launch the attack on the physical device. No exploit is available.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in zephyrproject-rtos Zephyr up to 4.4. This issue affects the function ext2_fetch_direntry of the file subsys/fs/ext2/ext2_diskops.c. The manipulation with an unknown input leads to a out-of-bounds vulnerability. Using CWE to declare the problem leads to CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-10645 since 06/02/2026. The exploitation is known to be easy. An attack has to be approached locally. No form of authentication is needed for a successful exploitation. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 322296 (Linux Distros Unpatched Vulnerability : CVE-2026-10645), which helps to determine the existence of the flaw in a target environment.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at Tenable (322296). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

• Project Management Software

Vendor

• zephyrproject-rtos

Name

• Zephyr

Version

• 4.0
• 4.1
• 4.2
• 4.3
• 4.4

License

• open-source

Website

• Product: https://github.com/zephyrproject-rtos/zephyr/

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If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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