A buffer overflow occurs in the Linux kernel's caam crypto module when an HMAC key larger than the block size is supplied. The key is duplicated with kmemdup, which incorrectly reads additional bytes from the source buffer, causing the resulting copy to overwrite adjacent memory. This memory corruption can compromise data integrity and potentially allow an attacker to execute arbitrary code in kernel space, leading to full system compromise, or cause a denial of service by crashing the kernel. The flaw manifests as a classic buffer overflow, involving CWE-125 (Out-of-bounds Read) and CWE-787 (Out-of-bounds Write).

All Linux kernel implementations that include the caam cryptographic accelerator and use HMAC keys larger than the acceptable block size are affected. No specific kernel versions are listed in the data, so the vulnerability may be present across multiple releases where caam is enabled.

The CVSS score of 7.8 indicates a high severity, and the EPSS score of < 1% shows the likelihood of exploitation is low but not zero. The vulnerability is not listed in KEV, meaning no known widespread exploitation. The overflow could allow an attacker with sufficient privileges to overwrite kernel memory, potentially achieving arbitrary code execution up to system compromise or causing a denial of service. The likely attack vector is a local or privileged process that can supply an oversized HMAC key to the caam crypto module. Exploitation requires that the system is running a kernel with the caam module enabled and a key longer than the block size is processed.