CVE-2026-6893
Description
A flaw was found in dracut. A remote attacker on the adjacent network can exploit this vulnerability by providing specially crafted DHCP (Dynamic Host Configuration Protocol) options, such as a malicious hostname, to a system using dracut's legacy DHCP path. These options are improperly handled and written into temporary shell scripts without proper escaping, leading to command injection. This allows the attacker to achieve root code execution within the initramfs, potentially compromising the system's boot and network behavior.
Statement
This is an Important vulnerability in dracut's legacy DHCP client script (dhclient-script.sh) that allows command injection. An attacker on the adjacent network can exploit this by providing specially crafted DHCP options, leading to root code execution within the initramfs. This primarily affects systems configured to use DHCP for network setup during the initial boot phase.
Mitigation
To mitigate this issue, ensure that systems configured to obtain network settings via DHCP in the initramfs are only booted on trusted networks. This vulnerability requires an attacker to control a DHCP server on the adjacent network segment. If network configuration via DHCP is not strictly necessary during the initramfs phase, consider using static network configuration.
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 | 7.5 | N/A | 7.5 |
| Attack Vector | Adjacent Network | N/A | Adjacent Network |
| Attack Complexity | High | N/A | High |
| 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:H/PR:N/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Confidentiality,Integrity,Availability,Non-Repudiation
Technical Impact: Execute Unauthorized Code or Commands; DoS: Crash, Exit, or Restart; Read Files or Directories; Modify Files or Directories; Read Application Data; Modify Application Data; Hide Activities
Attackers could execute unauthorized operating system commands, which could then be used to disable the product, or read and modify data for which the attacker does not have permissions to access directly. Since the targeted application is directly executing the commands instead of the attacker, any malicious activities may appear to come from the application or the application's owner.
Acknowledgements
Red Hat would like to thank AISLE Research for reporting this issue.
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