CVE-2025-0690
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 · uneditedThe read command is used to read the keyboard input from the user, while reads it keeps the input length in a 32-bit integer value which is further used to reallocate the line buffer to accept the next character. During this process, with a line big enough it's possible to make this variable to overflow leading to a out-of-bounds write in the heap based buffer. This flaw may be leveraged to corrupt grub's internal critical data and secure boot bypass is not discarded as consequence.
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 confidenceA heap-based buffer overflow vulnerability exists in GRUB2's read command where input length is stored in a 32-bit integer. When processing sufficiently large input lines, this integer can overflow, causing an out-of-bounds write that may corrupt critical data structures and potentially enable secure boot bypass.
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
- Physical
- Complexity
- Low
- Privileges
- High
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:P/AC:L/PR:H/UI:R/S:U/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 installationRun 'grub-install --version' or check for /boot/grub or /boot/efi/EFI/*/grub* directoriesAffected if GRUB2 is not installed on the system (not affected)
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Determine GRUB2 versionRun 'grub-install --version' or check the package manager (dpkg -l grub* or rpm -q grub2)Affected if The installed GRUB2 version predates the vendor patch for CVE-2025-0690; compare against patched versions if known
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Verify read command availabilityAccess GRUB command line (press 'c' at boot menu) and confirm the 'read' built-in command existsAffected if The read command is available in the GRUB shell, enabling the overflow condition
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Check for large input handling in GRUB configsInspect /boot/grub/grub.cfg and /etc/default/grub for custom menu entries or scripts that invoke the read command with user-controlled inputAffected if GRUB configuration files contain menu entries or scripts that pass potentially large input to the read command
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Confirm secure boot statusCheck if UEFI secure boot is enabled via 'mokutil --sb-state' or firmware settingsAffected if Secure boot is enabled and the system uses GRUB2 as the bootloader, making the bypass impact relevant
The system is affected if it runs an unpatched GRUB2 version that includes the read command and processes large inputs, especially in secure boot environments where the bypass impact applies.
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 dataApply the vendor patch that addresses the integer overflow in GRUB2's read command; recompile and redistribute the patched bootloader to all affected systems, verifying secure boot compatibility.
- Consultation6.0 h
- Implementation12.0 h
- Testing10.0 h
- Review / QA6.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $9,504.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-0690 — 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-2025-0690 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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- 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
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