The GRUB2's shim_lock verifier allows non-kernel files to be loaded on shim-powered secure boot systems.
The GRUB2's shim_lock verifier allows non-kernel files to be loaded on shim-powered secure boot systems. Allowing such files to be loaded may lead to unverified code and modules to be loaded in GRUB2 breaking the secure boot trust-chain.
- Published
- Jul 19, 2023
- Updated
- Jun 17, 2026
- EPSS
- 0.3% · 22th percentile
- CWE
- —
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Report tools
Action score
31
Monitor
Low priority for now.
- CVSS
- 31 / 40 · 7.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.3%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- 7.8
- CNA · canonical
- 6.7
- 1.1 point gap
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| gnu | grub2 | cpe:2.3:a:gnu:grub2 |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- gnu grub22.00 and later · before 2.06-3
Versions reported by the vendor
Affected version ranges reported by the assigning authority (canonical). Independent of NVD's CPE analysis and usually ahead of it.
GNU Project GNU GRUB
- before 2.06-3affected · semver
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:8 | grub2-common | before 1:2.02-123.el8_6.8.alma | 1:2.02-123.el8_6.8.alma |
| AlmaLinux:8 | grub2-efi-aa64 | before 1:2.02-123.el8_6.8.alma | 1:2.02-123.el8_6.8.alma |
| AlmaLinux:8 | grub2-efi-aa64-cdboot | before 1:2.02-123.el8_6.8.alma | 1:2.02-123.el8_6.8.alma |
| AlmaLinux:8 | grub2-efi-aa64-modules | before 1:2.02-123.el8_6.8.alma | 1:2.02-123.el8_6.8.alma |
| AlmaLinux:8 | grub2-efi-ia32 | before 1:2.02-123.el8_6.8.alma | 1:2.02-123.el8_6.8.alma |
| AlmaLinux:8 | grub2-efi-ia32-cdboot | before 1:2.02-123.el8_6.8.alma | 1:2.02-123.el8_6.8.alma |
| AlmaLinux:8 | grub2-efi-ia32-modules | before 1:2.02-123.el8_6.8.alma | 1:2.02-123.el8_6.8.alma |
| AlmaLinux:8 | grub2-efi-x64 | before 1:2.02-123.el8_6.8.alma | 1:2.02-123.el8_6.8.alma |
| AlmaLinux:8 | grub2-efi-x64-cdboot | before 1:2.02-123.el8_6.8.alma | 1:2.02-123.el8_6.8.alma |
| AlmaLinux:8 | grub2-efi-x64-modules | before 1:2.02-123.el8_6.8.alma | 1:2.02-123.el8_6.8.alma |
| AlmaLinux:8 | grub2-pc | before 1:2.02-123.el8_6.8.alma | 1:2.02-123.el8_6.8.alma |
| AlmaLinux:8 | grub2-pc-modules | before 1:2.02-123.el8_6.8.alma | 1:2.02-123.el8_6.8.alma |
| AlmaLinux:8 | grub2-ppc64le-modules | before 1:2.02-123.el8_6.8.alma | 1:2.02-123.el8_6.8.alma |
| AlmaLinux:8 | grub2-tools | before 1:2.02-123.el8_6.8.alma | 1:2.02-123.el8_6.8.alma |
| AlmaLinux:8 | grub2-tools-efi | before 1:2.02-123.el8_6.8.alma | 1:2.02-123.el8_6.8.alma |
| AlmaLinux:8 | grub2-tools-extra | before 1:2.02-123.el8_6.8.alma | 1:2.02-123.el8_6.8.alma |
| AlmaLinux:8 | grub2-tools-minimal | before 1:2.02-123.el8_6.8.alma | 1:2.02-123.el8_6.8.alma |
| AlmaLinux:8 | shim-aa64 | before 15.6-1.el8.alma | 15.6-1.el8.alma |
| AlmaLinux:8 | shim-ia32 | before 15.6-1.el8.alma | 15.6-1.el8.alma |
| AlmaLinux:8 | shim-unsigned-x64 | before 15.6-1.el8.alma | 15.6-1.el8.alma |
| AlmaLinux:8 | shim-x64 | before 15.6-1.el8.alma | 15.6-1.el8.alma |
| AlmaLinux:9 | grub2-common | before 1:2.06-27.el9_0.7.alma | 1:2.06-27.el9_0.7.alma |
| AlmaLinux:9 | grub2-efi-aa64 | before 1:2.06-27.el9_0.7.alma | 1:2.06-27.el9_0.7.alma |
| AlmaLinux:9 | grub2-efi-aa64-cdboot | before 1:2.06-27.el9_0.7.alma | 1:2.06-27.el9_0.7.alma |
+96
Same product
gnu: all recordsOther highest-scoring records for the same primary product.
- CVE-2024-56737GNU GRUB (aka GRUB2) through 2.12 has a heap-based buffer overflow in fs/hfs.c via crafted sblock data in an HFS filesystem.35Monitor
- CVE-2022-2601A buffer overflow was found in grub_font_construct_glyph().34Monitor
- CVE-2020-10713A flaw was found in grub2, prior to version 2.06.33Monitor
- CVE-2022-28733Integer underflow in grub_net_recv_ip4_packets32Monitor
- CVE-2021-20233A flaw was found in grub2 in versions prior to 2.06.32Monitor
- CVE-2020-25632A flaw was found in grub2 in versions prior to 2.06.32Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| GNU Project GNU GRUB | 2.06-3 | Vendor (CNA) |
| almalinux:grub2-common | 1:2.02-123.el8_6.8.alma · AlmaLinux:8 | Package registry (OSV) |
| almalinux:grub2-efi-aa64 | 1:2.02-123.el8_6.8.alma · AlmaLinux:8 | Package registry (OSV) |
| almalinux:grub2-efi-aa64-cdboot | 1:2.02-123.el8_6.8.alma · AlmaLinux:8 | Package registry (OSV) |
| almalinux:grub2-efi-aa64-modules | 1:2.02-123.el8_6.8.alma · AlmaLinux:8 | Package registry (OSV) |
| almalinux:grub2-efi-ia32 | 1:2.02-123.el8_6.8.alma · AlmaLinux:8 | Package registry (OSV) |
| almalinux:grub2-efi-ia32-cdboot | 1:2.02-123.el8_6.8.alma · AlmaLinux:8 | Package registry (OSV) |
| almalinux:grub2-efi-ia32-modules | 1:2.02-123.el8_6.8.alma · AlmaLinux:8 | Package registry (OSV) |
| almalinux:grub2-efi-x64 | 1:2.02-123.el8_6.8.alma · AlmaLinux:8 | Package registry (OSV) |
| almalinux:grub2-efi-x64-cdboot | 1:2.02-123.el8_6.8.alma · AlmaLinux:8 | Package registry (OSV) |
| almalinux:grub2-efi-x64-modules | 1:2.02-123.el8_6.8.alma · AlmaLinux:8 | Package registry (OSV) |
| almalinux:grub2-pc | 1:2.02-123.el8_6.8.alma · AlmaLinux:8 | Package registry (OSV) |
| almalinux:grub2-pc-modules | 1:2.02-123.el8_6.8.alma · AlmaLinux:8 | Package registry (OSV) |
| debian:grub2 | 2.06-3 · Debian:12 | Package registry (OSV) |
| opensuse:grub2 | 2.06-150400.11.5.2 · openSUSE:Leap 15.4 | Package registry (OSV) |
| red hat:grub2 | 1:2.02-123.el8_6.8 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:grub2-common | 1:2.02-123.el8_6.8 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:grub2-debuginfo | 1:2.02-123.el8_6.8 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:grub2-debugsource | 1:2.02-123.el8_6.8 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:grub2-efi-aa64 | 1:2.02-123.el8_6.8 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:grub2-efi-aa64-cdboot | 1:2.02-123.el8_6.8 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:grub2-efi-aa64-modules | 1:2.02-123.el8_6.8 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:grub2-efi-ia32 | 1:2.02-123.el8_6.8 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:grub2-efi-ia32-cdboot | 1:2.02-123.el8_6.8 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:grub2-efi-ia32-modules | 1:2.02-123.el8_6.8 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:grub2-efi-x64 | 1:2.02-123.el8_6.8 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:grub2-efi-x64-cdboot | 1:2.02-123.el8_6.8 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| rocky linux:grub2 | 1:2.02-123.el8_6.8 · Rocky Linux:8 | Package registry (OSV) |
| rocky linux:mokutil | 1:0.3.0-11.el8_6.1 · Rocky Linux:8 | Package registry (OSV) |
| rocky linux:shim | 0:15.6-1.el8 · Rocky Linux:8 | Package registry (OSV) |
+2
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
- Julian Andres Klodefinder
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Someone with local access to the system can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
—
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-28735
- security.netapp.com/advisory/ntap-20230825-0002/
- www.openwall.com/lists/oss-security/2022/06/07/5
Vendor advisories and official records. Exploit/PoC links are deliberately left out.