CVE-2025-38428 in Linux
Summary
by MITRE • 07/25/2025
In the Linux kernel, the following vulnerability has been resolved:
Input: ims-pcu - check record size in ims_pcu_flash_firmware()
The "len" variable comes from the firmware and we generally do trust firmware, but it's always better to double check. If the "len" is too large it could result in memory corruption when we do "memcpy(fragment->data, rec->data, len);"
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 01/03/2026
The vulnerability identified as CVE-2025-38428 resides within the Linux kernel's ims-pcu subsystem, specifically in the ims_pcu_flash_firmware() function where inadequate input validation creates a potential memory corruption risk. This issue affects the handling of firmware update operations for certain wireless communication devices that utilize the IMS PCU (Physical Control Unit) interface. The vulnerability stems from the function's failure to properly validate the length parameter received from external firmware sources, despite the kernel's general trust model for firmware data. The affected code path processes firmware records and performs memory operations that directly utilize the unvalidated length value, creating a scenario where malicious or malformed firmware could trigger buffer overflow conditions.
The technical flaw manifests in the direct usage of an unvalidated length variable within a memcpy operation, specifically at the line where memcpy(fragment->data, rec->data, len) executes. This pattern represents a classic buffer overflow vulnerability where the length parameter controls how many bytes are copied from the source to the destination buffer. When the len variable exceeds the allocated size of fragment->data, the memcpy operation overflows into adjacent memory regions, potentially corrupting kernel memory structures and compromising system stability. This vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and CWE-122, which addresses heap-based buffer overflow scenarios. The improper input validation creates an attack surface where an attacker could craft malicious firmware data to manipulate memory layout and potentially escalate privileges or cause system crashes.
The operational impact of this vulnerability extends beyond simple memory corruption, as it represents a potential pathway for privilege escalation within the kernel space. When memory corruption occurs during firmware flashing operations, it could allow an attacker to overwrite critical kernel data structures, function pointers, or control flow information. This presents a significant risk to systems that rely on firmware updates for device functionality, particularly in embedded environments or IoT deployments where firmware updates are frequent. The vulnerability is particularly concerning because it occurs during legitimate firmware update processes, meaning that even trusted firmware could be exploited if it contains maliciously crafted data. The potential for denial of service attacks is substantial, as system crashes or memory corruption could render devices inoperable. Additionally, the vulnerability could enable more sophisticated attacks such as kernel code execution or privilege escalation, making it a critical security concern for Linux kernel deployments.
Mitigation strategies for CVE-2025-38428 should focus on implementing robust input validation within the ims_pcu_flash_firmware() function to ensure that the length parameter remains within acceptable bounds before any memory operations occur. The recommended approach involves adding explicit bounds checking that validates the len parameter against the maximum expected buffer size before executing the memcpy operation. This validation should be implemented using defensive programming practices that consider both minimum and maximum allowable values for the length parameter. System administrators should ensure that kernel updates containing the fix are applied promptly, as the vulnerability exists in the core kernel functionality. Network administrators should monitor for any suspicious firmware update activities and implement firmware integrity checking mechanisms. The fix should be consistent with ATT&CK technique T1059.001, which involves command and scripting interpreter usage, as the vulnerability could be exploited through malicious firmware payloads that manipulate kernel execution flows. Organizations should also implement firmware signing and verification processes to prevent unauthorized firmware modifications, as the vulnerability demonstrates the importance of validating all data inputs regardless of their source trust level.