Skip to content
Noroxi
NVD / CVE Program· CNA AMD

CVE-2021-26340: A malicious hypervisor in conjunction with an unprivileged attacker process inside an SEV/SEV-ES guest VM may fail to flush the Translation…

HighCVSS 8.4 · v3.1—No exploit No fix recorded

Noroxi assessment

Priority: Monitor (action score 33/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.24% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • According to the record, no fixed version is available yet.

Low priority for now. Update when a fix is released; follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

A malicious hypervisor in conjunction with an unprivileged attacker process inside an SEV/SEV-ES guest VM may fail to flush the Translation Lookaside Buffer (TLB) resulting in unexpected behavior inside the virtual machine (VM).

Published
Dec 10, 2021
Updated
Jun 16, 2026
EPSS
0.2% · 16th percentile
CWE
—

Report tools

JSON

Action score

33

Monitor

Low priority for now.

CVSS
33 / 40 · 8.4 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • No fixed version yet

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2021-26340

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits every 10 minutes on paid plans, on the hour on the free plan.

Your free account also gets you

  • CVE alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools, at most 30 a day (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every MondayDon't want an account? RSS feed for amd records
Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

We use this product, ask for help

Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
amdepyc 7001 firmware
amdepyc 7001
amdepyc 7232p firmware
amdepyc 7232p
amdepyc 7251 firmware
amdepyc 7251
amdepyc 7261 firmware
amdepyc 7261
amdepyc 7252 firmware
amdepyc 7252
amdepyc 74f3 firmware
amdepyc 74f3

and 188 more

Versions reported by the vendor

Affected version ranges reported by the assigning authority (AMD). Independent of NVD's CPE analysis and usually ahead of it.

  • AMD AMD EPYC™

    • Processor and later · up to and including 3rd gen EPYCaffected
Affected versions · NVD (20)

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • amd epyc 7001 firmwareall versions
  • amd epyc 7232p firmwareall versions
  • amd epyc 7251 firmwareall versions
  • amd epyc 7252 firmwareall versions
  • amd epyc 7261 firmwareall versions
  • amd epyc 7262 firmwareall versions
  • amd epyc 7272 firmwareall versions
  • amd epyc 7281 firmwareall versions
  • amd epyc 7282 firmwareall versions
  • amd epyc 72f3 firmwareall versions
  • amd epyc 7301 firmwareall versions
  • amd epyc 7302 firmwareall versions
  • amd epyc 7302p firmwareall versions
  • amd epyc 7313 firmwareall versions
  • amd epyc 7313p firmwareall versions
  • amd epyc 7343 firmwareall versions
  • amd epyc 7351 firmwareall versions
  • amd epyc 7351p firmwareall versions
  • amd epyc 7352 firmwareall versions
  • amd epyc 7371 firmwareall versions

Same product

amd: all records

Other highest-scoring records for the same primary product.

  • CVE-2021-46774Insufficient DRAM address validation in System Management Unit (SMU) may allow an attacker to read/write from/to an invalid DRAM address…
    30Monitor
  • CVE-2020-12988A potential denial of service (DoS) vulnerability exists in the integrated chipset that may allow a malicious attacker to hang the system…
    30Monitor
  • CVE-2021-26356A TOCTOU in ASP bootloader may allow an attacker to tamper with the SPI ROM following data read to memory potentially resulting in S3 data…
    29Monitor

Published before and after this one in the same product

  • Later →CVE-2021-46744May 11, 2022 · An attacker with access to a malicious hypervisor may be able to infer data values used in a SEV guest on AMD CPUs by monitoring ciphertext…
    26Monitor
  • Later →CVE-2021-26403Jan 11, 2023 · Insufficient checks in SEV may lead to a malicious hypervisor disclosing the launch secret potentially resulting in compromise of VM…
    26Monitor
  • Later →CVE-2023-20521Nov 14, 2023 · TOCTOU in the ASP Bootloader may allow an attacker with physical access to tamper with SPI ROM records after memory content verification…
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
none

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Changed
Confidentiality impact
High
Integrity impact
High
Availability impact
None

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records