Security readout for executives and security teams
Plain-English summary
This GRUB2 flaw can let someone who already has privileged access interfere with Secure Boot protections by abusing the cutmem command. That could weaken a core boot-time trust control and create risk to confidentiality, integrity, and availability. The source bundle does not show active exploitation.
Executive priority
Treat as high priority for Secure Boot-reliant fleets, especially regulated endpoints, servers, and appliances. It is not presented as remotely exploitable, but it can undermine a foundational integrity control after privileged access is obtained.
Technical view
CVE-2020-27779 is an authorization flaw in GRUB2 where cutmem does not honor Secure Boot locking. The description says versions before 2.06 are affected, though the supplied affected-version entry is inconsistent. Successful abuse requires privileged access and knowledge of GRUB memory layout.
Likely exposure
Exposure is most relevant to Linux or appliance environments using GRUB2 with Secure Boot as a trusted control. Prioritize systems where local privileged access is plausible, shared administration exists, or boot integrity is compliance-sensitive.
Exploitation context
The source bundle marks CISA KEV as false and provides no cited evidence of in-the-wild exploitation. The attacker must already be privileged, so this is mainly a post-compromise or insider-risk boot-chain weakening issue.
Researcher notes
Key uncertainty: the bundle states versions prior to 2.06, while the affected entry lists grub 2.06. Validate against vendor advisories before scoping. Avoid assuming exploit availability or universal Linux exposure from this record alone.
Mitigation direction
- Apply GRUB2 security updates from the operating system or appliance vendor.
- Review Fedora, Gentoo, Red Hat, and NetApp guidance for affected supported packages.
- Prioritize Secure Boot-dependent servers, laptops, and appliances.
- Validate Secure Boot remains enabled after bootloader maintenance.
- Use vendor guidance if no fixed package is available for a platform.
Validation and detection
- Inventory systems using GRUB2 and Secure Boot.
- Compare installed GRUB2 packages against vendor advisory applicability.
- Confirm bootloader packages were updated through supported channels.
- Review bootloader configuration for unexpected changes.
- Check vendor appliance advisories for embedded GRUB2 exposure.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-285: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2020-27779 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://bugzilla.redhat.com/show_bug.cgi?id=1900698CVE reference · x_refsource_MISC
- FEDORA-2021-cab258a413CVE reference · vendor-advisory, x_refsource_FEDORA
- GLSA-202104-05CVE reference · vendor-advisory, x_refsource_GENTOO
- https://security.netapp.com/advisory/ntap-20220325-0001/CVE reference · x_refsource_CONFIRM
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Authorization
Improper Authorization represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.