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:

The Zephyr ext2 filesystem driver (subsys/fs/ext2) trusted the on-disk directory entry fields de_rec_len and de_name_len when walking a directory block. ext2_fetch_direntry() guarded only with de_name_len > EXT2_MAX_FILE_NAME, but de_name_len is a uint8_t and EXT2_MAX_FILE_NAME is 255, so the check is always false; the function then memcpy'd up to 255 name bytes and the lookup/readdir paths advanced traversal by an unvalidated de_rec_len. Each directory block is read into a block_size-sized slab buffer, and block_off can be driven near the block end by preceding entries' rec_len, so the 8-byte header read and the subsequent name memcpy can read up to ~263 bytes past the end of the block buffer into adjacent heap/slab memory. On the readdir path those bytes are returned to the caller in fs_dirent.name, leaking adjacent kernel heap memory; a de_rec_len of 0 also causes a zero-progress infinite loop (denial of service), and the unlink path's memmove(de, next, next_reclen) over unvalidated records is an additional OOB read/write source. The defect is reached by any path-based operation (open, stat, unlink, rename, mkdir) or directory listing on a mounted ext2 volume, so a crafted or corrupted ext2 image on attacker-supplied storage (SD card, USB mass storage, or otherwise mounted image) triggers it. Affected: Zephyr ext2 from its introduction in v3.5.0 through v4.4.0. The fix validates rec_len and name_len in the parser and rejects entries whose header does not fit the remaining block or whose rec_len crosses the block boundary in every traversal caller.

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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