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CVE Record

CVE-2025-0685: Grub2: jfs: integer overflow when handling symlinks may lead to heap based out-of-bounds write when reading data

A flaw was found in grub2. When reading data from a jfs filesystem, grub's jfs filesystem module uses user-controlled parameters from the filesystem geometry to determine the internal buffer size, however, it improperly checks for integer overflows. A maliciouly crafted filesystem may lead some of those buffer size calculations to overflow, causing it to perform a grub_malloc() operation with a smaller size than expected. As a result, the grub_jfs_lookup_symlink() function will write past the internal buffer length during grub_jfs_read_file(). This issue can be leveraged to corrupt grub's internal critical data and may result in arbitrary code execution, by-passing secure boot protections.

MediumCVSS 6.4Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2025-0685 is a GRUB2 bootloader flaw in JFS filesystem handling. A crafted filesystem can trigger a memory overwrite during bootloader file reads, potentially allowing code execution and Secure Boot bypass. The provided Red Hat entries mark listed RHEL and OpenShift products as unaffected.

Executive priority

Treat this as a targeted boot-chain risk, not a broad internet-exposed emergency. Prioritize validation on systems where attackers could alter boot media or boot filesystems, especially high-assurance devices relying on Secure Boot.

Technical view

GRUB2's JFS module derives buffer sizes from filesystem geometry but insufficiently checks integer overflows. Overflowed calculations may cause an undersized grub_malloc allocation, followed by an out-of-bounds heap write in grub_jfs_lookup_symlink during grub_jfs_read_file. CVSS is 6.4 with local, high-complexity, high-privilege attack requirements.

Likely exposure

Exposure appears limited to environments using GRUB2 with JFS parsing reachable by a highly privileged local actor or attacker able to supply crafted boot-accessible media. The supplied Red Hat product matrix states listed RHEL and OpenShift products are unaffected.

Exploitation context

No provided source reports active exploitation, and KEV is false. Exploitation requires local access, high privileges, high complexity, and a maliciously crafted filesystem. The impact could be serious where reachable because the stated outcome includes arbitrary code execution and Secure Boot bypass.

Researcher notes

Key uncertainty is vendor-specific exposure beyond the supplied Red Hat matrix. The public description identifies CWE-787 heap out-of-bounds write via integer overflow in GRUB2 JFS symlink handling, but the bundle does not provide patch versions or proof of exploitation.

Mitigation direction

  • Check GRUB2 and operating-system vendor advisories for affected builds and fixes.
  • Prioritize systems where boot media or filesystem contents can be modified by privileged users.
  • Restrict unauthorized physical, removable-media, and boot-partition modification access.
  • Do not assume Red Hat-listed products are affected where Red Hat marks them unaffected.
  • Track the GNU GRUB development reference for upstream remediation context.

Validation and detection

  • Inventory GRUB2 deployments and note whether JFS filesystem support is present or reachable.
  • Compare installed GRUB2 packages against vendor advisories for CVE-2025-0685.
  • Review boot-chain controls for unauthorized modification of boot filesystems or media.
  • Confirm whether any internal images rely on JFS during bootloader file access.
  • Document vendor status, including unaffected Red Hat products from the supplied matrix.
Prepared
Confidence
medium
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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 · low confidence lookup

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.

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description · low confidence lookup

Execution 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 lookup
description · low confidence lookup

Container 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 lookup
cve · low confidence lookup

CVE-2025-0685 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
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

Official CVE source material

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.

1CVSS vectors
5Timeline events
1ADP providers
4Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: total

CVSS vector scores

1 official score

We 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.

ScoreVersionSeverityVectorExploitImpactSource
6.4CVSS 3.1MediumCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H0.55.9redhat

Vulnerability scoring details

Base CVSS 3.1 score

6.4Medium
CVSS 3.1 vector shape for CVE-2025-0685Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. Source timelineredhat

    Reported to Red Hat.

  3. Source timelineredhat

    Made public.

  4. CVE publishedCVE Program

    The CVE record was published.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
Unknown vendorgrub2grub2, 0unaffected
Red HatRed Hat Enterprise Linux 10grub2unaffected
Red HatRed Hat Enterprise Linux 7grub2unaffected
Red HatRed Hat Enterprise Linux 8grub2unaffected
Red HatRed Hat Enterprise Linux 9grub2unaffected
Red HatRed Hat OpenShift Container Platform 4rhcosunaffected
Weakness

CWE details

CWE-787

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-787 · source CWE mapping

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.

Open CWE intelligenceSame-CWE CVEs