Out-of-bounds WriteWeakness · CWE-787

CVE-2025-0624

HIGH · 7.6 CVSS v3.1 Published 2025-02-19

Mitigation only

No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.

See remediation →

78/100

Remediation priority · High

Zero-click

Official description

NVD · unedited

A flaw was found in grub2. During the network boot process, when trying to search for the configuration file, grub copies data from a user controlled environment variable into an internal buffer using the grub_strcpy() function. During this step, it fails to consider the environment variable length when allocating the internal buffer, resulting in an out-of-bounds write. If correctly exploited, this issue may result in remote code execution through the same network segment grub is searching for the boot information, which can be used to by-pass secure boot protections.

Technical summary

dbcve analysis · high confidence

Buffer overflow vulnerability in GRUB2 during network boot where the code copies data from a user-controlled environment variable into an internal buffer using grub_strcpy() without checking the variable's length, resulting in an out-of-bounds write that can enable remote code execution and bypass secure boot protections.

MitigationPatch GRUB2 to properly validate and allocate buffer size based on environment variable length before copying. Network segmentation may limit exposure from malicious boot configuration requests.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown

From the vector

Attack vector: Adjacent
Complexity: High
Privileges: High
User interaction: None
Scope: Changed
Confidentiality: High
Integrity: High
Availability: High

CVSS:3.1/AV:A/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H

Am I affected?

dbcve checks

Work through these to decide whether this CVE applies to you.

Confirm GRUB2 is used for network booting

Inspect system boot configuration files in /boot/efi/EFI/*/ and check for GRUB2 (grubx64.efi, grub.efi) being used as the primary bootloader. Look for network boot entries in grub.cfg or boot entries configured for PXE/iPXE.

Affected if GRUB2 is the primary bootloader and network boot is configured or available
Identify installed GRUB2 version

Run 'grub2-install --version' or check the RPM/DEB package version (e.g., 'rpm -q grub2' or 'dpkg -l grub-pc'). For EFI systems, check the version embedded in the EFI binary.

Affected if The installed GRUB2 version is older than the patched version (no specific version in advisory, compare to vendor patch when available)
Verify network boot is enabled

Check for PXE/iPXE configuration files in /tftpboot, /pxelinux.cfg, or DHCP options pointing to network boot images. Examine DHCP/BOOTP responses for bootfile fields.

Affected if Network boot (PXE/iPXE) is enabled and GRUB2 loads over the network
Inspect GRUB network configuration for environment variable handling

Examine GRUB network configuration files (*.cfg in network boot paths) for 'export' statements or environment variables that could be set from network-provided values. Check for 'net_linux_env' or similar network-provided variable usage.

Affected if GRUB is configured to accept or process environment variables from network boot sources
Check for secure boot status

Verify secure boot state using 'mokutil --sb-state' or check UEFI firmware settings. This vulnerability can bypass secure boot protections.

Affected if Secure boot is enabled (the bypass impact applies)

A system is affected if it uses GRUB2 for network boot (PXE/iPXE) and processes user-controlled environment variables from network sources, with an unpatched GRUB2 version that lacks proper buffer length validation before grub_strcpy() calls.

Generated from the published advisory. Verify against your own configuration.

Remediation

From vendor data

Mitigation available No clean upgrade yet — mitigate in the meantime

Mitigation

Patch GRUB2 to properly validate and allocate buffer size based on environment variable length before copying. Network segmentation may limit exposure from malicious boot configuration requests.

Have this fixed Scoped from the published advisory

Consultation8.0 h
Implementation16.0 h
Testing12.0 h
Review / QA6.0 h

42.0 hours of engineering $7,360

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References

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-0624 in production — separate from our analysis above.

Notes0 Guidelines

Know something about CVE-2025-0624?

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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What this is

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.

What belongs here

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

At a glance

A fix existsA vendor remedy is published

Severity 7.6 High

Exploit likelihood EPSS, next 30 days 1.4%

Remediation

A high-priority fix

Have this fixed 42 hrs · Moderate

Typical engagement from $7,360

Get a fix See the full breakdown ↓

A high-priority vulnerability. Send your environment and a specialist will scope CVE-2025-0624 and return a fixed quote and timeline.

You’ll deal with our team directly and deploy the reviewed fix to staging first — never straight to production.

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.

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.

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.

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.

Check your environment

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.

Scan for this in your stack

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Practitioner notes

No notes yet

Official description

Technical summary

CVSS breakdown

Am I affected?

Remediation

References