CVE-2021-26379: Insufficient input validation of mailbox data in the SMU may allow an attacker to coerce the SMU to corrupt SMRAM, potentially leading to a
Noroxi assessment
Priority: Monitor (action score 39/100)
- 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: 0.68% (FIRST EPSS); higher than 52.5% of all records.
- Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
- According to CISA the attack is automatable: targets can be found by mass scanning.
- 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 input validation of mailbox data in the SMU may allow an attacker to coerce the SMU to corrupt SMRAM, potentially leading to a loss of integrity and privilege escalation.
- Published
- May 9, 2023
- Updated
- Jun 16, 2026
- EPSS
- 0.6% · 52th percentile
- CWE
- —
Report tools
Action score
39
Monitor
Low priority for now.
- CVSS
- 39 / 40 · 9.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.6%
CISA SSVC decision
- Exploitation
- none
- Automatable
- yes
- Technical impact
- total
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 72f3 firmware | cpe:2.3:o:amd:epyc_72f3_firmware |
| amd | epyc 72f3 | cpe:2.3:h:amd:epyc_72f3 |
| amd | epyc 7313 firmware | cpe:2.3:o:amd:epyc_7313_firmware |
| amd | epyc 7313 | cpe:2.3:h:amd:epyc_7313 |
| amd | epyc 7313p firmware | cpe:2.3:o:amd:epyc_7313p_firmware |
| amd | epyc 7313p | cpe:2.3:h:amd:epyc_7313p |
| amd | epyc 7343 firmware | cpe:2.3:o:amd:epyc_7343_firmware |
| amd | epyc 7343 | cpe:2.3:h:amd:epyc_7343 |
| amd | epyc 7373x firmware | cpe:2.3:o:amd:epyc_7373x_firmware |
| amd | epyc 7373x | cpe:2.3:h:amd:epyc_7373x |
| amd | epyc 73f3 firmware | cpe:2.3:o:amd:epyc_73f3_firmware |
| amd | epyc 73f3 | cpe:2.3:h:amd:epyc_73f3 |
and 84 more
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- amd epyc 7232p firmwarebefore romepi_1.0.0.e
- amd epyc 7252 firmwarebefore romepi_1.0.0.e
- amd epyc 7262 firmwarebefore romepi_1.0.0.e
- amd epyc 7272 firmwarebefore romepi_1.0.0.e
- amd epyc 7282 firmwarebefore romepi_1.0.0.e
- amd epyc 72f3 firmwarebefore milanpi_1.0.0.9
- amd epyc 7302 firmwarebefore romepi_1.0.0.e
- amd epyc 7302p firmwarebefore romepi_1.0.0.e
- amd epyc 7313 firmwarebefore milanpi_1.0.0.9
- amd epyc 7313p firmwarebefore milanpi_1.0.0.9
- amd epyc 7343 firmwarebefore milanpi_1.0.0.9
- amd epyc 7352 firmwarebefore romepi_1.0.0.e
- amd epyc 7373x firmwarebefore milanpi_1.0.0.9
- amd epyc 73f3 firmwarebefore milanpi_1.0.0.9
- amd epyc 7402 firmwarebefore romepi_1.0.0.e
- amd epyc 7402p firmwarebefore romepi_1.0.0.e
- amd epyc 7413 firmwarebefore milanpi_1.0.0.9
- amd epyc 7443 firmwarebefore milanpi_1.0.0.9
- amd epyc 7443p firmwarebefore milanpi_1.0.0.9
- amd epyc 7452 firmwarebefore romepi_1.0.0.e
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 2nd Gen AMD EPYC™
- variousaffected
AMD 3rd Gen AMD EPYC™
- variousaffected
Same product
amd: all recordsOther highest-scoring records for the same primary product.
- CVE-2023-20520Improper access control settings in ASP
Bootloader may allow an attacker to corrupt the return address causing a
stack-based buffer overrun 39Monitor
- CVE-2021-46756Insufficient validation of inputs in
SVC_MAP_USER_STACK in the ASP (AMD Secure Processor) bootloader may allow an
attacker with a malicious 36Monitor
- CVE-2021-46762Insufficient input validation in the SMU may
allow an attacker to corrupt SMU SRAM potentially leading to a loss of
integrity or denial of s36Monitor
Published before and after this one in the same product
- Later →CVE-2021-26397May 9, 2023 · Insufficient address validation, may allow an
attacker with a compromised ABL and UApp to corrupt sensitive memory locations
potentially res28Monitor
- Later →CVE-2021-46763May 9, 2023 · Insufficient input validation in the SMU may
enable a privileged attacker to write beyond the intended bounds of a shared
memory buffer pote30Monitor
- Later →CVE-2021-46764May 9, 2023 · Improper validation of DRAM addresses in SMU may
allow an attacker to overwrite sensitive memory locations within the ASP
potentially result30Monitor
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
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- 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
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
—
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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.
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.