CVE-2021-26362
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA malicious or compromised UApp or ABL may be used by an attacker to issue a malformed system call which results in mapping sensitive System Management Network (SMN) registers leading to a loss of integrity and availability.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceThis is an AMD silicon vulnerability where a malicious or compromised UApp (likely a security application) or ABL (Advanced Boot Loader) can issue a malformed system call that maps sensitive System Management Network (SMN) registers. The SMN is an AMD internal network for system management functions, and improper mapping of these registers leads to integrity and availability loss.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE dataall versionsall versionsall versionsall versionsall versionsall versionsall versionsall versionsCVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify AMD processor modelOpen System Information or run 'wmic cpu get name' in command prompt to confirm if the system uses an affected AMD Ryzen or Athlon processor (2200u, 2300u, 5125c, 5400u, 3050ge, 3150ge, 3150g)Affected if The processor is one of the listed affected models and the BIOS/firmware has not been updated to a patched version provided by AMD
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Check BIOS/UEFI firmware versionAccess BIOS/UEFI setup during boot or use 'wmic bios get smbiosbiosversion' command to retrieve the current BIOS versionAffected if The BIOS version is older than the latest AMD-provided update that addresses CVE-2021-26362 validation of system calls
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Check AMD Radeon Software versionOpen AMD Radeon Software or navigate to Programs and Features to verify if AMD Radeon Software is installed and note its versionAffected if AMD Radeon Software is installed (all versions are affected per the CVE description) and no AMD-provided update has been applied
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Verify UApp or ABL component integrityReview installed security applications (UApps) and boot loader (ABL) components for signs of tampering or unauthorized modification; check digital signatures where possibleAffected if A compromised or malicious UApp or ABL is present that could issue the malformed system call to map SMN registers
The environment is affected if any AMD processor from the listed affected models or AMD Radeon Software is present, and the system has not applied the specific AMD firmware/BIOS update that implements proper validation of system calls to prevent unauthorized SMN register mapping.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataApply AMD-provided firmware/BIOS updates that address proper validation of system calls and prevent unauthorized SMN register mapping. Verify that UApps and ABL components are from trusted, unaltered sources.
- Consultation8.0 h
- Implementation16.0 h
- Testing12.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $11,200.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-26362 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-26362 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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