CVE 2026 124747

A flaw was found in BusyBox. When resuming a download over File Transfer Protocol (FTP), the wget utility fails to verify that the resume offset does not exceed the file size reported by the server, resulting in an integer calculation error. A malicious FTP server or an on-path network attacker can exploit this issue by returning crafted file size metadata, triggering a heap-based buffer overflow with attacker-controlled data. Successful exploitation may allow an attacker to execute arbitrary code or crash the application, resulting in a denial of service (DoS).

This flaw is assessed as having an Important severity because heap-based memory corruption could allow remote code execution or application crashes, although successful exploitation requires the client to interact with a compromised FTP host or an unencrypted on-path adversary. In Red Hat environments, BusyBox is not utilized as the standard system core utility and is primarily confined to minimal specialized container and boot images. Because triggering the vulnerability requires an active file resumption transfer under specific file size discrepancy conditions, exposure is limited to explicit client-side invocations interacting with untrusted endpoints.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Bugzilla 2569520 : busybox: Heap buffer overflow in wget FTP resume when the resume offset exceeds the reported file size

CWE-787 : Out-of-bounds Write

Common Vulnerability Scoring System (CVSS) Score Details

Info alert: Important note

CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications ).

The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 Score Breakdown

Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

cve.org: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Understanding the Weakness (CWE)

Technical Impact: Modify Memory; Execute Unauthorized Code or Commands

Write operations could cause memory corruption. In some cases, an adversary can modify control data such as return addresses in order to execute unexpected code.

Technical Impact: DoS: Crash, Exit, or Restart

Attempting to access out-of-range, invalid, or unauthorized memory could cause the product to crash.

Technical Impact: Unexpected State

Subsequent write operations can produce undefined or unexpected results.

Red Hat would like to thank Seokwoo Jang (AXGATE) for reporting this issue.

Frequently Asked Questions

"Under investigation" doesn't necessarily mean that the product is affected by this vulnerability. It only means that our Analysis Team is still working on determining whether the product is affected and how it is affected.

The term 'Affected' means that our Analysis team has determined that this product, such as Red Hat Enterprise Linux 8 or OpenShift Container Platform 4, is affected by this vulnerability and a fix may be released to address this issue in the near future. This includes all minor releases of this product unless noted otherwise in the Statement text.

Upgrade to a supported product version that includes a fix for this vulnerability (recommended).

Apply a mitigation (if one exists).

Customers with the Technical Account Manager (TAM) RHEL Security Select Add-on can review this CVE directly with their TAM.

Apply a mitigation (if one exists).

Red Hat Engineering focuses on addressing high-priority issues based on the impact and product lifecycle expectations. Therefore, lower-priority issues will not receive immediate fixes.

Customers with the technical account manager (TAM) RHEL Security Select Add-on can review this CVE directly with their TAM.

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