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UBUNTU-CVE-2026-64535

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UBUNTU-CVE-2026-64535

Published: 27 Jul 2026Last Modified: 6 Nov 2026

Upstream:

Aliases:

Summary:

Details: In the Linux kernel, the following vulnerability has been resolved: nvmet-tcp: Fix potential UAF when ddgst mismatch Shivam Kumar found via vulnerability testing: When data digest is enabled on an NVMe/TCP connection and a digest mismatch occurs on a non-final H2C_DATA PDU during an R2T-based data transfer, the digest error handler in nvmet_tcp_try_recv_ddgst() calls nvmet_req_uninit() — which performs percpu_ref_put() on the submission queue — but does NOT mark the command as completed. It does not set cqe->status, does not modify rbytes_done, and does not clear any flag. When the subsequent fatal error triggers queue teardown, nvmet_tcp_uninit_data_in_cmds() iterates all commands, checks nvmet_tcp_need_data_in() for each one, and finds that the already-uninited command still appears to need data (because rbytes_done < transfer_len and cqe->status == 0). It therefore calls nvmet_req_uninit() a second time on the same command — a double percpu_ref_put against a single percpu_ref_get.

Affected packages

Package

Name: linux-hwe-edge

Purl: pkg:deb/ubuntu/linux-hwe-edge?arch=source&distro=xenial

Affected ranges

Type: ECOSYSTEM

Events:

Introduced- 0

Fixed -None

Affected versions

4.8.0-28.30~16.04.1

4.8.0-30.32~16.04.1

4.8.0-32.34~16.04.1

4.8.0-34.36~16.04.1

Common Vulnerability Scoring System

Attack Vector

Network

Adjacent

Local

Physical

Privileges Required

None

Low

High

User Interaction

None

Required

Scope

Unchanged

Changed

Confidentiality

None

Low

High

Integrity

None

Low

High

Availability

None

Low

High