Security readout for executives and security teams
Plain-English summary
This is a bootloader parsing flaw in GRUB2’s ROMFS support. A malicious local actor with high privileges could craft filesystem data that makes GRUB allocate too little memory and corrupt critical bootloader data, potentially bypassing Secure Boot. The sources rate it medium because exploitation is local, complex, and privileged.
Executive priority
Treat this as a targeted local boot-chain risk, not a broad internet emergency. It matters most for high-assurance endpoints, servers with strict Secure Boot assumptions, and environments where privileged users or build systems can modify bootable media.
Technical view
During ROMFS symlink lookup, GRUB2 uses user-controlled filesystem geometry in buffer-size calculations and insufficiently checks integer overflow. An overflow can make grub_malloc allocate a smaller buffer than expected, leading to heap out-of-bounds writes during grub_disk_read. The stated impact includes arbitrary code execution and Secure Boot bypass.
Likely exposure
Exposure appears limited to systems where GRUB may read attacker-controlled ROMFS data before boot. The CVSS vector requires local access, high attack complexity, and high privileges. Red Hat entries in the bundle mark listed RHEL and OpenShift products as unaffected, so product impact should be verified with each vendor.
Exploitation context
The bundle does not show KEV listing or active exploitation. The described path requires a maliciously crafted filesystem and enough local control to influence what GRUB reads. That makes opportunistic remote exploitation unlikely, but compromise of boot media, images, or privileged local administration paths remains relevant.
Researcher notes
The strongest evidence is the CVE description and Red Hat reference data. Affected-product evidence is limited in the provided bundle, and listed Red Hat products are marked unaffected. No exploit-in-the-wild signal is provided. Avoid expanding impact beyond GRUB2 ROMFS symlink handling without vendor confirmation.
Mitigation direction
- Check your OS vendor advisory for GRUB2 package status and guidance.
- Prioritize systems where untrusted users can alter boot media or disk images.
- Restrict administrative access to boot partitions, removable boot media, and image-building pipelines.
- Monitor GRUB2, distribution, and firmware vendor advisories for fixes or configuration guidance.
- Do not assume Red Hat impact where the cited affected table says unaffected.
Validation and detection
- Inventory systems using GRUB2 and identify distributions and package versions.
- Compare each platform against its vendor advisory, not only the generic CVE entry.
- Review whether GRUB can access ROMFS content in your boot workflows.
- Check controls around boot partitions, removable media, and image build artifacts.
- Document any systems lacking vendor guidance as unresolved 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-787: 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 lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupContainer behavior lookup
The affected technology mentions containers, so container-specific ATT&CK technique review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2025-0686 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
- Medium
- CVSS
- 6.4 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
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.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H0.55.9redhatVulnerability scoring details
Base CVSS 3.1 score
6.4MediumVector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- Source timelineredhat
Reported to Red Hat.
- Source timelineredhat
Made public.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://access.redhat.com/security/cve/CVE-2025-0686CVE reference, redhat · vdb-entry, x_refsource_REDHAT
- RHBZ#2346121CVE reference, redhat · issue-tracking, x_refsource_REDHAT
- https://lists.gnu.org/archive/html/grub-devel/2025-02/msg00024.htmlCVE reference, redhat
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.
Out-of-bounds Write
Out-of-bounds Write represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.