Linux EUVD-2026-49031

In the Linux kernel, the following vulnerability has been resolved:

nvmet-auth: validate reply message payload bounds against transfer length

nvmet_auth_reply() accesses the variable-length rval[] array using attacker-controlled hl (hash length) and dhvlen (DH value length) fields without verifying they fit within the allocated buffer of tl bytes.

A malicious NVMe-oF initiator can craft a DHCHAP_REPLY message with a small transfer length but large hl/dhvlen values, causing out-of-bounds heap reads when the target processes the DH public key (rval + 2*hl) or performs the host response memcmp.

With DH authentication configured, the OOB pointer is passed directly to sg_init_one() and read by crypto_kpp_compute_shared_secret(), reaching up to 526 bytes past the buffer. This is exploitable pre-authentication.

Add bounds validation ensuring sizeof(*data) + 2*hl + dhvlen <= tl before any access to the variable-length fields.

Discovered by Atuin - Automated Vulnerability Discovery Engine.