CVE-2026-64319: nvmet-auth: validate reply message payload bounds against transfer length

Vulnerability summary

CVE-2026-64319 is a critical (CVSS 9.1) Out-of-bounds Read vulnerability in linux. EPSS estimates a 0.56% chance of exploitation in the next 30 days, higher than 46.8% of scored vulnerabilities.

Timeline

1. 25-07-2026
   PublishedVulnerability first disclosed.
2. 30-10-2026
   Last modifiedVulnerability information updated.

Description

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.

• CWE-125Out-of-bounds ReadThe product reads data past the end, or before the beginning, of the intended buffer.