CVE-2021-26400

Data leakage via speculative load reordering

Published May 11, 2022 · Updated Sep 17, 2024

Information disclosure in AMD CPU products allows local users to observe stale data when processors concurrently access shared memory. The processor can speculatively reorder load instructions without the required ordering barriers, exposing a stale value from shared memory. Exploitation requires local execution alongside another processor context operating on the same shared memory, and the disclosed impact is limited to data leakage.

CVSS severity4.0
Medium
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Information disclosure in AMD CPU products allows local users to observe stale data when processors concurrently access shared memory. The processor can speculatively reorder load instructions without the required ordering barriers, exposing a stale value from shared memory. Exploitation requires local execution alongside another processor context operating on the same shared memory, and the disclosed impact is limited to data leakage.

The record

CVE
CVE-2021-26400
Published
May 11, 2022
Updated
Sep 17, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
Unavailable
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 11, 2022CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

2.1NIST NVDAV:L/AC:L/Au:N/C:P/I:N/A:N
4.0NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo