CVE-2024-57256

High

Published: 18 February 2025

Published

18 February 2025

Modified

03 November 2025

KEV Added

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Patch

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CVSS Score 7.1 CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

EPSS Score 0.0006 19.0th percentile

Risk Priority 14 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2024-57256 is a high-severity Integer Overflow or Wraparound (CWE-190) vulnerability in Denx U-Boot. Its CVSS base score is 7.1 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Pre-OS Boot (T1542); ranked at the 19.0th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).

Threat & Defense at a Glance

What attackers do: exploitation maps to Pre-OS Boot (T1542) and 1 other technique. What defenders deploy: see the NIST 800-53 controls recommended below.

Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

SI-2 Flaw Remediation good match

prevent

Requires timely patching of the integer overflow in U-Boot's ext4fs_read_symlink function to prevent exploitation via crafted ext4 filesystems.

SI-10 Information Input Validation good match

prevent

Mandates validation of filesystem inputs such as inode sizes to block integer overflows during zalloc operations in bootloader parsing.

SI-16 Memory Protection partial match

prevent

Implements memory protections that mitigate overwrites from zero-byte malloc allocations triggered by the integer overflow.

MITRE ATT&CK Enterprise TechniquesAI

T1542 Pre-OS Boot Stealth

Adversaries may abuse Pre-OS Boot mechanisms as a way to establish persistence on a system.

attack.mitre.org →

T1068 Exploitation for Privilege Escalation Privilege Escalation

Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.

attack.mitre.org →

Why these techniques?

Integer overflow in U-Boot ext4 parsing enables memory overwrite/ACE at boot time via crafted FS image (physical access), directly mapping to pre-OS boot compromise and privilege escalation via exploitation.

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

NVD Description

An integer overflow in ext4fs_read_symlink in Das U-Boot before 2025.01-rc1 occurs for zalloc (adding one to an le32 variable) via a crafted ext4 filesystem with an inode size of 0xffffffff, resulting in a malloc of zero and resultant memory overwrite.

Deeper analysisAI

CVE-2024-57256 is an integer overflow vulnerability (CWE-190) in the ext4fs_read_symlink function within Das U-Boot versions prior to 2025.01-rc1. The issue arises when processing a crafted ext4 filesystem featuring an inode size of 0xffffffff, which causes an overflow during a zalloc operation that adds one to an le32 variable. This results in a malloc allocation of zero bytes, enabling a subsequent memory overwrite.

Exploitation requires physical access to the target device (AV:P) and involves high attack complexity (AC:H), with no privileges (PR:N) or user interaction (UI:N) needed. The attack has a changed scope (S:C) and high impacts on confidentiality, integrity, and availability (C:H/I:H/A:H), scoring 7.1 under CVSS 3.1. A successful exploit could allow an attacker to overwrite memory, potentially leading to arbitrary code execution or system compromise on affected U-Boot bootloaders.

Mitigation is addressed in a commit (35f75d2a46e5859138c83a75cd2f4141c5479ab9) in the U-Boot repository, which users should apply by updating to Das U-Boot 2025.01-rc1 or later. Announcements on oss-security (2025/02/17) detail the vulnerability disclosure, while Debian LTS tracking (2025/05) indicates backported fixes for affected distributions. Security practitioners should verify bootloader versions in embedded or boot environments and test crafted filesystem inputs during validation.