Enterprise LinuxOperating system · Redhat
CVE-2020-27779
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 flaw was found in grub2 in versions prior to 2.06. The cutmem command does not honor secure boot locking allowing an privileged attacker to remove address ranges from memory creating an opportunity to circumvent SecureBoot protections after proper triage about grub's memory layout. The highest threat from this vulnerability is to data confidentiality and integrity as well as system 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 · high confidenceA flaw exists in grub2 versions prior to 2.06 where the cutmem command does not honor secure boot locking mechanisms. This allows a privileged attacker to remove address ranges from memory, potentially circumventing SecureBoot protections by exploiting knowledge of grub's memory layout.
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
Enterprise LinuxOperating system
= 7.0= 8.0
Enterprise Linux Server AusOperating system
= 7.2= 7.3= 7.4= 7.6= 7.7= 8.2
Enterprise Linux Server EusOperating system
= 7.6= 7.7= 8.1
Enterprise Linux Server TusOperating system
= 7.4= 7.6= 7.7= 8.2
Enterprise Linux WorkstationOperating system
= 7.0
FedoraOperating system
= 33= 34< 2.06all 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
- High
- Privileges
- High
- User interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/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 grub2 installed versionRun 'rpm -q grub2' or 'rpm -q grub2-efi-x64' to determine the installed grub2 package version. On systems with EFI, also check /boot/efi/EFI/*/grubx64.efi for the binary version.Affected if The installed version is earlier than 2.06 (for example, 2.04, 2.05, or earlier)
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Confirm Secure Boot is enabledRun 'mokutil --sb-state' on Linux systems, or check the system firmware/UEFI settings directly. On some systems, 'efivar --print --name=8be4df61-93ca-11d2-aa0d-00e09832b8af' can show Secure Boot status.Affected if Secure Boot is currently enabled in the system firmware
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Verify cutmem module presenceCheck if the cutmem.mod file exists in the grub modules directory. Common paths: /boot/grub2/x86_64-efi/cutmem.mod or /usr/lib/grub/x86_64-efi/cutmem.modAffected if The cutmem module file exists in the grub installation (indicating the vulnerable command is available)
A system is affected if it runs grub2 version prior to 2.06 with Secure Boot enabled and the cutmem module is present in the grub installation.
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 data2.06
Upgrade grub2 to version 2.06 or later and ensure proper secure boot re-enrollment if necessary.
Fix this in Enterprise Linux
Scoped from the published advisory
- Consultation3.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,880.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-27779 — 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-2020-27779 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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- Version or environment caveats, and links to real fixes
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