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

Status: published. Published: 2025-03-03. Updated: 2026-11-05.

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.

## Remediation

- workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. (source: CNA: redhat)

## Affected products and versions

-  /  (grub2): ≥ 0; ≤ 2.12 (affected, semver). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 10 (grub2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 (grub2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (grub2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (grub2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 4 (openshift/ose-rhel-coreos-8): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 4 (openshift/ose-rhel-coreos-9): Version range not reported. Source: CNA: redhat

## Severity and prioritization

- CVSS 3.1: 6.4 (medium); CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H; source: CNA: redhat

- CISA KEV: No listing in collected sources

- EPSS: 0.29% as of 2026-11-05; percentile 21.46%

- SSVC: exploitation none; automatable no; technical impact total; source ADP: CISA-ADP

- Weaknesses: CWE-787

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://access.redhat.com/security/cve/CVE-2025-0685 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2346120 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

- https://lists.gnu.org/archive/html/grub-devel/2025-02/msg00024.html (CNA: redhat)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2025-0685; retrieved 2026-11-05; source updated 2026-11-05

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2025-0685; retrieved 2026-11-05; source updated Not reported

Revision: 99e9aeb1635f9c522bd58a489795db8e533d6083cc4d82ed05362d4a0930aa3f

Canonical: https://y2.dev/cve/CVE-2025-0685

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