High [CVE-2026-64304] qat - validate RSA CRT component lengths

In the Linux kernel, the following vulnerability has been resolved: crypto: qat - validate RSA CRT component lengths The generic RSA key parser (rsa_helper.c) bounds each CRT component (p, q, dp, dq, qinv) by the modulus size n_sz, but qat_rsa_setkey_crt() allocates half-size DMA buffers (key_sz / 2) and right-aligns each component with: memcpy(dst + half_key_sz - len, src, len) When a CRT component is larger than half_key_sz the subtraction underflows and memcpy writes past the DMA buffer, causing memory corruption.

Add a len > half_key_sz check next to the existing!len check for each of the five CRT components so the driver falls back to the non-CRT path instead of writing out of bounds. A flaw was found in the Linux kernel's QAT (QuickAssist Technology) crypto module.

This vulnerability occurs in the RSA key parser when handling CRT (Chinese Remainder Theorem) components. An underflow can happen during a memory copy operation if an RSA CRT component is larger than its allocated buffer, leading to memory corruption.

This could potentially allow an attacker to cause system instability or execute arbitrary code. Red Hat severity: Important — CVSS 7 (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H).

Weakness: CWE-787.