Cyber Resilience

CVE-2026-10645

Memory Safety in Zephyrproject Zephyr ≤ 4.4.1

Public PoCMemory Safety
Published
23 June 2026
Modified
14 July 2026
Patch / advisory
CVSS Score v3.1 4.9
Click a component to see what it means
Raw vectorCVSS:3.1/AV:P/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H
EPSS Score 0.0015 5th percentile
Risk Priority 35 floored blend · peak EPSS

Summary

CVE-2026-10645 is a medium-severity Out-of-bounds Read (CWE-125) vulnerability in Zephyrproject Zephyr. Its CVSS base score is 4.9 (Medium).

Operationally, ranked at the 5th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) and MP-7 (Media Use) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

Insufficient information to map techniques.
Confidence: LOW · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2026-9263Same product: Zephyrproject Zephyr
CVE-2026-10652Same product: Zephyrproject Zephyr
CVE-2025-1675Same product: Zephyrproject Zephyr
CVE-2025-1674Same product: Zephyrproject Zephyr
CVE-2026-10657Same product: Zephyrproject Zephyr
CVE-2025-1673Same product: Zephyrproject Zephyr
CVE-2026-5071Same product: Zephyrproject Zephyr
CVE-2023-0396Same product: Zephyrproject Zephyr
CVE-2024-6443Same product: Zephyrproject Zephyr
CVE-2026-10658Same product: Zephyrproject Zephyr

Affected Assets

zephyrproject
zephyr
≤ 4.4.1

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • SI-10 Information Input Validation
  • SI-7 Software, Firmware, and Information Integrity
  • MP-7 Media Use
Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)

Mitigating Controls (NIST 800-53 r5) AI

prevent

Requires validation of all input fields (de_rec_len, de_name_len, block boundaries) before memcpy or traversal advancement in ext2_fetch_direntry.

prevent

Verifies integrity of ext2 filesystem images before directory traversal operations such as lookup or readdir.

MP-7 Media Use partial match
prevent

Restricts mounting and use of ext2 images from untrusted or removable media that could contain malformed directory entries.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure-development practices such as bounds checking and memory-safe languages directly prevent out-of-bounds reads.

ID.RA-01 partial match
prevents

Vulnerability scanning and recording can discover instances of out-of-bounds reads after code is deployed.

PR.PS-02 partial match
prevents

Routine patching replaces vulnerable code containing out-of-bounds read flaws.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

detects

Security testing in development and acceptance includes fuzzing and static analysis that detect out-of-bounds read defects before release.

A.8.15 Logging partial match
detects

Logging can record evidence of an out-of-bounds read but does not prevent the weakness itself.

prevents

Secure development life cycle mandates input validation and bounds checking that directly prevent out-of-bounds reads.

prevents

Application security requirements include explicit bounds and memory-safety specifications that mitigate buffer over-reads.

prevents

Secure system architecture and engineering principles require memory-safe design patterns and runtime protections against out-of-bounds access.

prevents

Secure coding standards explicitly forbid unsafe pointer arithmetic and mandate bounds-checked reads, eliminating CWE-125.

References