CVE-2026-29004
Description
A flaw was found in BusyBox. A heap buffer overflow vulnerability exists in the Dynamic Host Configuration Protocol version 6 (DHCPv6) client, specifically within the option_to_env() function. Network-adjacent attackers can exploit this by sending a crafted DHCPv6 response containing a malformed D6_OPT_DNS_SERVERS option. This can lead to memory corruption, potentially allowing for arbitrary code execution or denial of service on affected embedded systems lacking heap hardening.
Mitigation
To mitigate this vulnerability, restrict network access to systems running BusyBox as a DHCPv6 client, ensuring that only trusted DHCPv6 servers can communicate with it. If the DHCPv6 client functionality is not essential for the system's operation, consider disabling the `udhcpc6` service or configuring it to only accept responses from known, trusted sources. Consult product-specific documentation for details on managing network services and configurations. Any changes to network service configurations may require a service restart to take effect, potentially impacting network connectivity.
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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 8.8 | N/A | 8.8 |
| 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 | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Integrity,Availability,Confidentiality
Technical Impact: DoS: Crash, Exit, or Restart; Execute Unauthorized Code or Commands; Read Memory; Modify Memory
If the incorrect calculation is used in the context of memory allocation, then the software may create a buffer that is smaller or larger than expected. If the allocated buffer is smaller than expected, this could lead to an out-of-bounds read or write (CWE-119), possibly causing a crash, allowing arbitrary code execution, or exposing sensitive data.
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
