CVE-2021-46778

Execution unit scheduler contention may lead to a side channel vulnerability found on AMD CPU...

5.6 Medium

Execution unit scheduler contention may lead to a side channel vulnerability found on AMD CPU microarchitectures codenamed “Zen 1”, “Zen 2” and “Zen 3” that use simultaneous multithreading (SMT). By measuring the contention level on scheduler queues an attacker may potentially leak sensitive information.

Attack profile

How easy it is to exploit

Attack vector: Local
Complexity: High
Privileges needed: Low
User interaction: None

What an attacker can affect

Confidentiality: High
Integrity: None
Availability: None

Exploit likelihood

0.24%Down 2.3 points since Aug 10, 2022

What each source reports

NVD Score used 5.6

Record: CVE-2021-46778
CVSS 3.1: 5.6 MediumCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N
Weakness: CWE-203
Updated: 2026-11-02

CVE List No score

Record: CVE-2021-46778
Updated: 2026-11-02

EUVDEUVD-2021-33434 No score

Record: EUVD-2021-33434
Updated: 2026-11-03

GitHub AdvisoriesGHSA-745h-3gvr-9mc6 7.5

Execution unit scheduler contention may lead to a side channel vulnerability found on AMD CPU...

Record: GHSA-745h-3gvr-9mc6
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Weakness: CWE-203
Updated: 2026-11-02

Affected products

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History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases, published	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-46778 is a medium vulnerability (CVSS 5.6) in Amd Processors, published August 9, 2022. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.24%, the 15th percentile. No source names a fixed version.