CVE-2025-7020: BYD DiLink OS · Incorrect Encryption Implementation

Attack Vector: Physical

The attack requires the attacker to physically touch or manipulate the vulnerable system. Physical interaction may be brief (e.g., evil maid attack) or persistent.

Attack Complexity: Low

The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.

Attack Requirements: None

The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.

Privileges Required: None

The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.

User Interaction: None

The vulnerable system can be exploited without interaction from any human user, other than the attacker.

Vulnerable system confidentiality: High

There is a total loss of confidentiality, resulting in all information within the Vulnerable System being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.

Vulnerable system integrity: None

There is no loss of integrity within the Vulnerable System.

Vulnerable system availability: None

There is no impact to availability within the Vulnerable System.

Subsequent system confidentiality: Low

There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the Subsequent System.

Subsequent system integrity: None

There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.

Subsequent system availability: None

There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Automatable: Yes

Attackers can reliably automate all 4 steps of the kill chain. These steps are reconnaissance, weaponization, delivery, and exploitation (e.g., the vulnerability is “wormable”).

Value Density: Diffuse

The vulnerable system has limited resources. That is, the resources that the attacker will gain control over with a single exploitation event are relatively small. An example of Diffuse (think: limited) Value Density would be an attack on a single email client vulnerability.

Vulnerability Response Effort: High

The actions required to respond to a vulnerability are significant and/or difficult, and may possibly lead to an extended, scheduled service impact. This would need to be considered for scheduling purposes including honoring any embargo on deployment of the selected response. Alternatively, response to the vulnerability in the field is not possible remotely. The only resolution to the vulnerability involves physical replacement (e.g. units deployed would have to be recalled for a depot level repair or replacement). Examples include: a highly privileged driver update, microcode or UEFI BIOS updates, or software upgrades requiring careful analysis and understanding of any potential infrastructure impact before implementation. A UEFI BIOS update that impacts Trusted Platform Module (TPM) attestation without impacting disk encryption software such as Bit locker is a good recent example. Irreparable failures such as non-bootable flash subsystems, failed disks or solid-state drives (SSD), bad memory modules, network devices, or other non-recoverable under warranty hardware, should also be scored as having a High effort.

Definitions: FIRST CVSS v4.0 specification.