Time-of-check Time-of-use (TOCTOU) Affecting rv package, versions *


Severity

Recommended
medium

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.15% (5th percentile)

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  • Snyk IDSNYK-RHEL10-RV-18562186
  • published6 Aug 2026
  • disclosed19 Jul 2026

Introduced: 19 Jul 2026

NewCVE-2026-64034  (opens in a new tab)
CWE-367  (opens in a new tab)

How to fix?

There is no fixed version for RHEL:10 rv.

NVD Description

Note: Versions mentioned in the description apply only to the upstream rv package and not the rv package as distributed by RHEL. See How to fix? for RHEL:10 relevant fixed versions and status.

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

net: mana: Fix TOCTOU double-fetch of hwc_msg_id from DMA buffer

In mana_hwc_rx_event_handler(), resp->response.hwc_msg_id is read from DMA-coherent memory and bounds-checked, then mana_hwc_handle_resp() re-reads the same field from the same DMA buffer for test_bit() and pointer arithmetic.

DMA-coherent memory is mapped uncacheable on x86 and is shared, unencrypted, in Confidential VMs (SEV-SNP/TDX), so each load goes directly to host-visible memory. A H/W can modify the value between the check and the use, bypassing the bounds validation.

Fix this by reading hwc_msg_id exactly once using READ_ONCE() into a stack-local variable in mana_hwc_rx_event_handler(), and passing the validated value as a parameter to mana_hwc_handle_resp().

CVSS Base Scores

version 3.1