CVE-2025-38428: 
Linux Kernel vulnerability analysis and mitigation

CVE-2025-38428 is an out-of-bounds write vulnerability in the Linux kernel's ims-pcu input driver, specifically within the ims_pcu_flash_firmware() function. The flaw arises because the len variable sourced from firmware data is not validated before being used in a memcpy operation, potentially enabling memory corruption if the value is excessively large. It was published on July 25, 2025, and affects Linux kernel versions from 3.10 through multiple stable branches up to (but not including) the patched releases. The vulnerability carries a CVSS v3.1 base score of 7.8 (High) (Red Hat CVE, Feedly).

The root cause is classified as CWE-787 (Out-of-bounds Write). In ims_pcu_flash_firmware(), the driver reads a len field directly from firmware record data (rec->data) and passes it without bounds checking to memcpy(fragment->data, rec->data, len). If a maliciously crafted or corrupted firmware image supplies an oversized len value, the copy operation will write beyond the allocated buffer, corrupting adjacent kernel memory. Exploitation requires local access and the ability to supply or influence firmware loaded by the ims-pcu driver (e.g., via the firmware loading subsystem). The fix adds a record size validation check before the memcpy call (Red Hat CVE, kernel patches).

Successful exploitation could allow a low-privileged local attacker to corrupt kernel memory, potentially leading to arbitrary code execution in kernel context, privilege escalation, system crashes (denial of service), or unauthorized access to sensitive kernel data. The vulnerability has high impact across confidentiality, integrity, and availability dimensions. Given kernel-level code execution, a successful exploit could fully compromise the affected host and enable lateral movement within a network (Red Hat CVE, Feedly).

There is no public proof-of-concept exploit or evidence of in-the-wild exploitation at this time. The EPSS score is approximately 0.024% (0.000240), indicating a very low probability of exploitation in the near term. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. Exploitation requires local access and the ability to influence firmware loading, which limits the practical attack surface (Feedly, Red Hat CVE).

Patches have been released for all affected stable kernel branches. Administrators should update to the following minimum versions: 5.4.295, 5.10.239, 5.15.186, 6.1.142, 6.6.95, 6.12.35, or 6.15.4. Distribution-specific updates are available from Red Hat, Ubuntu (USN-7774-1, USN-7774-2, USN-7775-2, USN-7776-1, USN-7834-1), Debian, and Oracle Linux. As interim mitigations, restrict local system access, limit firmware flashing capabilities, and consider using mandatory access control frameworks (SELinux or AppArmor) to constrain the attack surface (Red Hat CVE, Ubuntu USN-7774-1, Debian Tracker).