The product defines a large address region protected from modification by the same register lock control bit. This results in a conflict between the functional requirement that some addresses need to be writable by software during operation and the security requirement that the system configuration lock bit must be set during the boot process.

Integrated circuits and hardware IPs can expose the device configuration controls that need to be programmed after device power reset by a trusted firmware or software module (commonly set by BIOS/bootloader) and then locked from any further modification. In hardware design, this is commonly implemented using a programmable lock bit which enables/disables writing to a protected set of registers or address regions. When the programmable lock bit is set, the relevant address region can be implemented as a hardcoded value in hardware logic that cannot be changed later.
A problem can arise wherein the protected region definition is not granular enough. After the programmable lock bit has been set, then this new functionality cannot be implemented without change to the hardware design.

Primary

Architecture and Design
Such issues are introduced during hardware architecture and design since software controls and configuration are defined during these phases and identified later during Testing or System Configuration phases.

Access Control
Other
System security configuration cannot be defined in a way that does not conflict with functional requirements of device.

Architecture and Design

The defining of protected locked registers should be reviewed or tested early in the design phase with software teams to ensure software flows are not blocked by the security locks.
As an alternative to using register lock control bits and fixed access control regions, the hardware design could use programmable security access control configuration so that device trusted firmware can configure and change the protected regions based on software usage and security models.

For example, consider a hardware unit with a 32 kilobyte configuration address space where the first 8 kilobyte address contains security sensitive controls that must only be writable by device bootloader. One way to protect the security configuration could be to define a 32 bit system configuration locking register (SYS_LOCK) where each bit lock locks the corresponding 1 kilobyte region.

Address
Register

0x0000
SYS_LOCK: 32 bit system configuration lock register, each bit is write-1-once

0x0004
SECURITY_FEATURE_ENABLE: 32 bit register controlling enabling of security features

...

0x0310
SW_MODE: 32 bit Software Mode indication register

Address region
Lock bit

0x0000 - 0x03FF
SYS_LOCK[0]

0x0400 - 0x07FF
SYS_LOCK[1]

...

0x7C00 - 0x7FFF
SYS_LOCK[31]

If a register exists within the first kilobyte address range (e.g. SW_MODE, address 0x310) and needs to be software writable at runtime, then this register cannot be written in a securely configured system since SYS_LOCK register lock bit 0 must be set to protect other security settings (e.g. SECURITY_FEATURE_ENABLE, address 0x0004). The only fix would be to change the hardware logic or not set the security lock bit.

Allowed
This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.

Arun Kanuparthi, Hareesh Khattri, Parbati Kumar Manna, Narasimha Kumar V Mangipudi
Intel Corporation
2019-12-12
4.0
2020-02-24

CWE Content Team
MITRE
2020-08-20
updated Related_Attack_Patterns

CWE Content Team
MITRE
2022-04-28
updated Related_Attack_Patterns

CWE Content Team
MITRE
2023-01-31
updated Relationships

CWE Content Team
MITRE
2023-04-27
updated Relationships

CWE Content Team
MITRE
2023-06-29
updated Mapping_Notes

CWE Content Team
MITRE
2025-12-11
4.19
2025-12-11
updated Weakness_Ordinalities