CVE-2021-26403: Insufficient checks in SEV may lead to a malicious hypervisor disclosing the launch secret potentially resulting in compromise of VM confide
Noroxi assessment
Priority: Monitor (action score 26/100)
- 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: 0.12% (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
Insufficient checks in SEV may lead to a malicious hypervisor disclosing the launch secret potentially resulting in compromise of VM confidentiality.
- Published
- Jan 11, 2023
- Updated
- Jun 16, 2026
- EPSS
- 0.1% · 2th percentile
- CWE
- CWE-345
Report tools
Action score
26
Monitor
Low priority for now.
- CVSS
- 26 / 40 · 6.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.1%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
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.
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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 helpAffected 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.
| Vendor | Product | CPE |
|---|---|---|
| amd | epyc 7302p | cpe:2.3:h:amd:epyc_7302p |
| amd | epyc 7001 firmware | cpe:2.3:o:amd:epyc_7001_firmware |
| amd | epyc 7001 | cpe:2.3:h:amd:epyc_7001 |
| amd | epyc 7251 firmware | cpe:2.3:o:amd:epyc_7251_firmware |
| amd | epyc 7251 | cpe:2.3:h:amd:epyc_7251 |
| amd | epyc 7261 firmware | cpe:2.3:o:amd:epyc_7261_firmware |
| amd | epyc 7261 | cpe:2.3:h:amd:epyc_7261 |
| amd | epyc 7281 firmware | cpe:2.3:o:amd:epyc_7281_firmware |
| amd | epyc 7281 | cpe:2.3:h:amd:epyc_7281 |
| amd | epyc 7301 firmware | cpe:2.3:o:amd:epyc_7301_firmware |
| amd | epyc 7301 | cpe:2.3:h:amd:epyc_7301 |
| amd | epyc 7351 firmware | cpe:2.3:o:amd:epyc_7351_firmware |
and 70 more
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- amd epyc 7001 firmwarebefore naplespi_1.0.0.e
- amd epyc 7002 firmwarebefore romepi_1.0.0.9
- amd epyc 7232p firmwarebefore romepi_1.0.0.9
- amd epyc 7251 firmwarebefore naplespi_1.0.0.e
- amd epyc 7252 firmwarebefore romepi_1.0.0.9
- amd epyc 7261 firmwarebefore naplespi_1.0.0.e
- amd epyc 7262 firmwarebefore romepi_1.0.0.9
- amd epyc 7272 firmwarebefore romepi_1.0.0.9
- amd epyc 7281 firmwarebefore naplespi_1.0.0.e
- amd epyc 7282 firmwarebefore romepi_1.0.0.9
- amd epyc 7301 firmwarebefore naplespi_1.0.0.e
- amd epyc 7302 firmwarebefore romepi_1.0.0.9
- amd epyc 7302p firmwarebefore romepi_1.0.0.9
- amd epyc 7351 firmwarebefore naplespi_1.0.0.e
- amd epyc 7351p firmwarebefore naplespi_1.0.0.e
- amd epyc 7352 firmwarebefore romepi_1.0.0.9
- amd epyc 7371 firmwarebefore naplespi_1.0.0.e
- amd epyc 7401 firmwarebefore naplespi_1.0.0.e
- amd epyc 7401p firmwarebefore naplespi_1.0.0.e
- amd epyc 7402 firmwarebefore romepi_1.0.0.9
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 1st Gen EPYC
- variousaffected
AMD 2nd Gen EPYC
- variousaffected
Same product
amd: all recordsOther highest-scoring records for the same primary product.
- CVE-2021-26340A malicious hypervisor in conjunction with an unprivileged attacker process inside an SEV/SEV-ES guest VM may fail to flush the Translation 33Monitor
- CVE-2021-46774Insufficient DRAM address validation in System
Management Unit (SMU) may allow an attacker to read/write from/to an invalid
DRAM address, po30Monitor
- CVE-2020-12988A potential denial of service (DoS) vulnerability exists in the integrated chipset that may allow a malicious attacker to hang the system wh30Monitor
Published before and after this one in the same product
- ← EarlierCVE-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-2021-26356May 9, 2023 · A TOCTOU in ASP bootloader may allow an attacker
to tamper with the SPI ROM following data read to memory potentially resulting
in S3 data c29Monitor
- 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, po22Monitor
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.
No history yet (it accumulates with the daily EPSS job).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
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
- none
- 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
- None
- Availability impact
- None
Weakness class (CWE)
CWE-345 · Insufficient Verification of Data AuthenticityCVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/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.
Attack patterns (CAPEC)
- JSON Hijacking (aka JavaScript Hijacking)CAPEC-111likelihood: High · High
- Cache PoisoningCAPEC-141likelihood: High · High
- DNS Cache PoisoningCAPEC-142likelihood: High · High
- Content SpoofingCAPEC-148likelihood: Medium · Medium
- Spoofing of UDDI/ebXML MessagesCAPEC-218Medium
- Application API Message Manipulation via Man-in-the-MiddleCAPEC-384Low
- Transaction or Event Tampering via Application API ManipulationCAPEC-385Medium
- Application API Navigation RemappingCAPEC-386Medium
Change log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.