SB20260720199 - Time-of-check Time-of-use (TOCTOU) Race Condition in Linux kernel microsoft mana driver

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Main Vulnerability Database SB20260720199

SB20260720199 - Time-of-check Time-of-use (TOCTOU) Race Condition in Linux kernel microsoft mana driver

Published: July 20, 2026

Security Bulletin ID SB20260720199
CSH Severity
Low
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Data manipulation

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Time-of-check Time-of-use (TOCTOU) Race Condition (CVE-ID: CVE-2026-64034)

CWE-ID: CWE-367 - Time-of-check Time-of-use (TOCTOU) Race Condition

CVSSv4: 2.1 [CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to bypass bounds validation.

The vulnerability exists due to a time-of-check time-of-use double-fetch in mana_hwc_rx_event_handler() and mana_hwc_handle_resp() when reading hwc_msg_id from a DMA-coherent buffer. A remote attacker can modify the DMA-visible hwc_msg_id value between reads to bypass bounds validation.

Exploitation requires hardware or a host environment able to alter shared, unencrypted DMA-coherent memory between the check and the subsequent use, such as in confidential VM environments.


Remediation

Install update from vendor's website.

References