CVE-2026-124747
Description
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).
Statement
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
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.
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 | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | N/A | N/A |
| Attack Vector | Network | N/A | N/A |
| Attack Complexity | High | N/A | N/A |
| Privileges Required | None | N/A | N/A |
| User Interaction | Required | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | High | N/A | N/A |
| Integrity Impact | High | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Integrity
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.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
Attempting to access out-of-range, invalid, or unauthorized memory could cause the product to crash.
Other
Technical Impact: Unexpected State
Subsequent write operations can produce undefined or unexpected results.
Acknowledgements
Red Hat would like to thank Seokwoo Jang (AXGATE) for reporting this issue.
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