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Resource Allocation Without LimitsWeakness · CWE-770

CVE-2021-26381

HIGH · 7.1 CVSS v4.0 Published 2026-02-10
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
73/100
Remediation priority · Elevated
Zero-click

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 · unedited
Improper system call parameter validation in the Trusted OS may allow a malicious driver to perform mapping or unmapping operations on a large number of pages, potentially resulting in kernel memory corruption.

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 confidence

Improper system call parameter validation in the Trusted OS allows a malicious driver to perform mapping or unmapping operations on a large number of pages, potentially resulting in kernel memory corruption. This vulnerability in the trusted execution environment's system call interface lacks bounds checking on page count parameters.

MitigationApply vendor-provided patches for the Trusted OS (likely AMD Platform Security Processor or equivalent). Review and restrict driver signing policies to prevent loading of malicious drivers.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS 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
High
Privileges
High
Authentication
X
User interaction
None
Scope
X

CVSS:4.0/AV:L/AC:H/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify AMD Platform Security Processor presence
    Check system firmware/UEFI settings or use 'dmidecode' or manufacturer tools to determine if AMD Secure Processor (PSP) is enabled on the system
    Affected if AMD Secure Processor is not present or is disabled in firmware - the vulnerability does not apply in this case
  2. Check Trusted OS firmware version
    Use AMD-provided tools (like 'amd-psp-redfish' or manufacturer firmware update utilities) to query the Platform Security Processor firmware version. Compare against vendor release notes for fixed versions.
    Affected if The installed PSP firmware version predates the vendor patch for CVE-2021-26381 and no subsequent firmware update has been applied
  3. Verify driver code signing enforcement
    On Windows: check 'bcdedit /enum all' for 'Testsigning' status or use 'sigverif.exe'. On Linux: check 'secure_boot' status via 'mokutil --sb-state' and review module signing configuration in '/etc/modprobe.d/'
    Affected if Driver signing enforcement is disabled or set to permissive mode, allowing unsigned or third-party drivers to load
  4. Audit loaded third-party drivers
    On Windows: use 'driverquery /v' or 'Get-WmiObject Win32_PnPSignedDriver'. On Linux: check 'lsmod' and review '/proc/modules' for any untrusted or unsigned kernel modules.
    Affected if Unsigned or untrusted third-party drivers are loaded into the Trusted OS environment context
  5. Review driver loading policy
    Check system policy for driver loading restrictions. On Windows: verify 'Driver Signature Enforcement' is enabled in Group Policy (gpedit.msc). On Linux: verify 'lockdown' kernel parameter and module loading restrictions.
    Affected if Driver loading policy permits unsigned drivers or does not enforce module signature verification

The system is affected if it runs an unpatched AMD Platform Security Processor firmware and allows loading of unsigned or malicious drivers that can interface with the Trusted OS system call interface.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply vendor-provided patches for the Trusted OS (likely AMD Platform Security Processor or equivalent). Review and restrict driver signing policies to prevent loading of malicious drivers.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA6.0 h
30.0 hours of engineering $5,120
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-26381 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • 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
  • No spam, self-promotion, credentials, or personal data