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

From: Greg Kroah-Hartman <[email protected]>

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.

The Linux kernel CVE team has assigned CVE-2026-64319 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.0 with commit db1312dd95488b5e6ff362ff66fcf953a46b1821 and fixed in 6.6.145 with commit 80cd28b56ab62d3e7ed0a7bf05282e6d3ee5b2a0
	Issue introduced in 6.0 with commit db1312dd95488b5e6ff362ff66fcf953a46b1821 and fixed in 6.12.96 with commit 999f6205ede984a786f35f727b01f971b98e215d
	Issue introduced in 6.0 with commit db1312dd95488b5e6ff362ff66fcf953a46b1821 and fixed in 6.18.39 with commit 6d7649c1231dac14d906985d2936967e23041c26
	Issue introduced in 6.0 with commit db1312dd95488b5e6ff362ff66fcf953a46b1821 and fixed in 7.1.4 with commit caa71b3a43ea5c13fe7141cb019ebcb03b8ac857
	Issue introduced in 6.0 with commit db1312dd95488b5e6ff362ff66fcf953a46b1821 and fixed in 7.2-rc1 with commit 3a413ece2504c70aa34a20be4dafec04e8c741f9

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-64319
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/nvme/target/fabrics-cmd-auth.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/80cd28b56ab62d3e7ed0a7bf05282e6d3ee5b2a0
	https://git.kernel.org/stable/c/999f6205ede984a786f35f727b01f971b98e215d
	https://git.kernel.org/stable/c/6d7649c1231dac14d906985d2936967e23041c26
	https://git.kernel.org/stable/c/caa71b3a43ea5c13fe7141cb019ebcb03b8ac857
	https://git.kernel.org/stable/c/3a413ece2504c70aa34a20be4dafec04e8c741f9