CVE-2021-33639
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 · uneditedREMAP cmd of SVM driver can be used to remap read only memory as read-write, then cause read only memory/file modified.
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 confidenceThe SVM driver's REMAP command improperly allows read-only memory regions to be remapped as read-write, bypassing memory protection controls and enabling modification of read-only memory or files.
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 data<= 4.19.90-2211.4.0.0177>= 5.0, <= 5.10.0-60.67.0.92CVSS 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
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
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.
-
Identify the operating system distributionRun 'cat /etc/os-release' or 'uname -a' to confirm the system is OpenAtom OpenEulerAffected if The system is not running an OpenEuler distribution - this CVE only affects OpenEuler kernels
-
Check the installed kernel versionRun 'uname -r' to get the kernel version and compare against the affected ranges: <= 4.19.90-2211.4.0.0177 OR >= 5.0.0 through <= 5.10.0-60.67.0.92Affected if The kernel version falls within either of the two affected ranges (4.19.90-2211.4.0.0177 and below, or 5.0.0 through 5.10.0-60.67.0.92)
-
Verify if SVM/AMD-V virtualization is in useCheck for SVM-enabled VMs or nested virtualization: look for 'svm' in /proc/cpuinfo (AMD-V) or check hypervisor configuration if this kernel hosts virtual machinesAffected if SVM/AMD-V virtualization is actively enabled and the kernel is being used to manage virtual machines - the REMAP command flaw only applies when SVM virtualization features are in use
-
Check SVM driver module statusRun 'lsmod | grep -i svm' or check /sys/module/ to verify the SVM kernel module is loadedAffected if The SVM driver module is loaded and active on the system
A user is affected if they are running an OpenEuler kernel within the specified version ranges AND have SVM/AMD-V virtualization features enabled and operational.
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 dataUpdate the SVM driver/hypervisor to a patched version that properly enforces read-only memory protection in the REMAP command logic.
- Consultation4.0 h
- Implementation12.0 h
- Testing8.0 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 $7,808.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-33639 — 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-2021-33639 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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.
- 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