CVE-2026-124741
Description
A flaw was found in BusyBox. The udhcpc6 DHCPv6 client does not properly validate the size of network options sent by a server before copying them into memory. A malicious DHCPv6 server on the local network can exploit this flaw by sending a crafted reply, triggering a stack-based buffer overflow. This vulnerability could allow an attacker to achieve arbitrary code execution with root privileges or cause a denial of service (DoS) crash.
Statement
This vulnerability is rated as having an Important impact for Red Hat products because, while exploitation is constrained to adjacent network attackers on the local link, the client process typically runs with superuser privileges, allowing a rogue DHCPv6 server to potentially achieve arbitrary code execution or cause a denial of service. In standard Red Hat Enterprise Linux installations, BusyBox is not used as the default network management or DHCP client, as networking is handled by NetworkManager. Consequently, exposure is limited to specialized or embedded environments where BusyBox's udhcpc6 utility is explicitly invoked for IPv6 network configuration.
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 | 7.6 | N/A | 7.6 |
| Attack Vector | Adjacent Network | N/A | Adjacent Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | Low | N/A | Low |
| Integrity Impact | Low | N/A | Low |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
cve.org: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/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 ducanhluu for reporting this issue.
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