The vulnerability lies in the Linux kernel’s s390 crypto AES implementation. It stems from the fact that skcipher_walk_virt() return codes are not verified before the ecb_aes_crypt() and ctr_aes_crypt() routines proceed. If skcipher_walk_virt() fails, the walk structure may contain uninitialized data, and subsequent processing can read invalid memory. This can produce incorrect cryptographic results, cause the kernel to crash, or expose kernel data through memory leakage.

Any Linux kernel running the s390 architecture and employing the AES module prior to the commit that added the return‑code check is potentially affected. The vulnerability exists in the source code path for standard AES operations on s390; no specific kernel version range is listed, so deployments using older or unpatched kernels should be considered at risk.

The CVSS score is 5.5, representing moderate severity, while the EPSS score is below 1%, indicating a very low probability of exploitation. The vulnerability is not listed in the CISA KEV catalog. The flaw requires kernel code execution on the s390 architecture, implying that a local or privileged attacker is needed. Exposing uninitialized memory or provoking incorrect cryptographic behavior could lead to a kernel crash (denial of service) or potentially leakage of kernel memory. Because the walk structure may be left in an undefined state when skcipher_walk_virt() fails, the attacker could induce consistent failures to trigger these outcomes. However, no published proof of concept is currently available.