CVE-2026-43492

A flaw was found in the Linux kernel. A local user could trigger an integer underflow in the mpi_read_raw_from_sgl() function within the lib/crypto: mpi component. This occurs when invoking a KEYCTL_PKEY_ENCRYPT system call with a larger output length than input length and providing a zero-filled input buffer. Successful exploitation leads to a Denial of Service (DoS) due to the kernel spinning indefinitely.

This vulnerability is rated as Moderate impact because exploitation requires local authenticated access to execute keyctl operations, restricting the blast radius strictly to a denial of service without compromising data confidentiality or system integrity. On affected systems, an unprivileged user can force the kernel into an infinite loop by submitting malformed asymmetric key cryptographic requests. Earlier platforms, including Red Hat Enterprise Linux 8 and 9, do not incorporate the triggering interface logic and are not affected.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.