Unisoc (Shanghai) Technologies Co., Ltd.

This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability. It refers to the loss of availability of the impacted component itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of an impacted component.

Availability

There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

High

This metric describes the conditions beyond the attacker’s control that must exist in order to exploit the vulnerability. Such conditions may require the collection of more information about the target or computational exceptions. The assessment of this metric excludes any requirements for user interaction in order to exploit the vulnerability. If a specific configuration is required for an attack to succeed, the Base metrics should be scored assuming the vulnerable component is in that configuration.

Attack Complexity

Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.

This metric reflects the context by which vulnerability exploitation is possible. The Base Score increases the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable component.

Attack Vector

The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document).

Local

This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.

Confidentiality

There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.

This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information.

Integrity

There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.

This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability.

Privileges Required

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

None

Does a successful attack impact a component other than the vulnerable component? If so, the Base Score increases and the Confidentiality, Integrity and Authentication metrics should be scored relative to the impacted component.

Scope

An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.

Changed

This metric captures the requirement for a user, other than the attacker, to participate in the successful compromise the vulnerable component. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.

User Interaction

The vulnerable system can be exploited without any interaction from any user.

The product writes data past the end, or before the beginning, of the intended buffer.

Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index…

Consider adhering to the following rules when allocating and managing an application's memory: Double check that the buffer is as large as specified.; When using functions that accept a number of bytes to copy, such as strncpy(), be aware that if the destination buffer size is equal to the source buffer size, it may…

Out-of-bounds Write

XML Security Cheat Sheet

Enforce schema on XML structure/field

Mass Assignment Cheat Sheet

Enforce schema on type/contents of structured data

Whitelist all external (HTTP) input

MITRE CWE

MITRE CAPEC

OWASP Top 10

OWASP OpenCRE

Metasploit Framework

ProjectDiscovery nuclei-templates

Exploit-DB

PoC-in-GitHub

CVE Program CNA list

FIRST CVSS v3.1

FIRST CVSS v4.0

CVE-2026-121803 is a high-severity vulnerability in Unisoc (Shanghai) Technologies Co., Ltd. Storage related to the UFS Field Firmware Update (FFU) functionality. It involves an out-of-bounds write caused by missing bounds checking on the PRDT table size. This flaw can lead to local code execution or denial of service without requiring additional privileges or user interaction.

This vulnerability (CWE-787) exists in the UFS FFU functionality of Unisoc Storage products. The root cause is a lack of bounds checking on the PRDT table size, which allows an out-of-bounds write. Exploitation could enable an attacker with local access to execute arbitrary code or cause a denial of service. The CVSS v3.1 base score is 8.8, reflecting high impact on confidentiality, integrity, and availability. No public exploits or patches are currently known or provided.

CVE Database V5

CVE-2026-121803 is a high-severity vulnerability in Unisoc (Shanghai) Technologies Co., Ltd. Storage related to the UFS Field Firmware Update (FFU) functionality. It involves an out-of-bounds write caused by missing bounds checking on the PRDT table size. This flaw can lead to local code execution o

CVE-2026-121803 has been rejected

Official rejection reason