Grub2: ufs: integer overflow may lead to heap based out-of-bounds write when handling symlinks
A flaw was found in grub2. When performing a symlink lookup, the grub's UFS module checks the inode's data size to allocate the internal buffer to read the file content, however, it fails to check if the symlink data size has overflown. When this occurs, grub_malloc() may be called with a smaller value than needed. When further reading the data from the disk into the buffer, the grub_ufs_lookup_symlink() function will write past the end of the allocated size. An attack can leverage this by crafting a malicious filesystem, and as a result, it will corrupt data stored in the heap, allowing for arbitrary code execution used to by-pass secure boot mechanisms.
- Published
- Feb 19, 2025
- Updated
- Jun 29, 2026
- EPSS
- 0.3% · 23th percentile
- CWE
- CWE-787
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Report tools
Action score
25
Monitor
Low priority for now.
- CVSS
- 25 / 40 · 6.4 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.3%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · redhat
- 6.4
- NVD has not scored this yet; the score shown is the CNA’s.
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Affected systems
—
Versions reported by the vendor
Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.
Red Hat Red Hat Enterprise Linux 10
- 1:2.12-15.el10_0 and laternot affected · rpm
Red Hat Red Hat Enterprise Linux 7
- all versionsunknown
Red Hat Red Hat Enterprise Linux 8
- all versionsunknown
Red Hat Red Hat Enterprise Linux 9
- 1:2.06-104.el9_6 and laternot affected · rpm
Red Hat Red Hat OpenShift Container Platform 4
- all versionsaffected
www.gnu.org/software/grub/ grub2
- up to and including 2.12affected · semver
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:10 | grub2-common | before 1:2.12-15.el10_0.alma.1 | 1:2.12-15.el10_0.alma.1 |
| AlmaLinux:10 | grub2-efi-aa64-modules | before 1:2.12-15.el10_0.alma.1 | 1:2.12-15.el10_0.alma.1 |
| AlmaLinux:10 | grub2-efi-x64-modules | before 1:2.12-15.el10_0.alma.1 | 1:2.12-15.el10_0.alma.1 |
| AlmaLinux:10 | grub2-pc-modules | before 1:2.12-15.el10_0.alma.1 | 1:2.12-15.el10_0.alma.1 |
| AlmaLinux:10 | grub2-ppc64le-modules | before 1:2.12-15.el10_0.alma.1 | 1:2.12-15.el10_0.alma.1 |
| AlmaLinux:9 | grub2-common | before 1:2.06-104.el9_6.alma.1 | 1:2.06-104.el9_6.alma.1 |
| AlmaLinux:9 | grub2-efi-aa64 | before 1:2.06-104.el9_6.alma.1 | 1:2.06-104.el9_6.alma.1 |
| AlmaLinux:9 | grub2-efi-aa64-cdboot | before 1:2.06-104.el9_6.alma.1 | 1:2.06-104.el9_6.alma.1 |
| AlmaLinux:9 | grub2-efi-aa64-modules | before 1:2.06-104.el9_6.alma.1 | 1:2.06-104.el9_6.alma.1 |
| AlmaLinux:9 | grub2-efi-x64 | before 1:2.06-104.el9_6.alma.1 | 1:2.06-104.el9_6.alma.1 |
| AlmaLinux:9 | grub2-efi-x64-cdboot | before 1:2.06-104.el9_6.alma.1 | 1:2.06-104.el9_6.alma.1 |
| AlmaLinux:9 | grub2-efi-x64-modules | before 1:2.06-104.el9_6.alma.1 | 1:2.06-104.el9_6.alma.1 |
| AlmaLinux:9 | grub2-pc | before 1:2.06-104.el9_6.alma.1 | 1:2.06-104.el9_6.alma.1 |
| AlmaLinux:9 | grub2-pc-modules | before 1:2.06-104.el9_6.alma.1 | 1:2.06-104.el9_6.alma.1 |
| AlmaLinux:9 | grub2-ppc64le | before 1:2.06-104.el9_6.alma.1 | 1:2.06-104.el9_6.alma.1 |
| AlmaLinux:9 | grub2-ppc64le-modules | before 1:2.06-104.el9_6.alma.1 | 1:2.06-104.el9_6.alma.1 |
| AlmaLinux:9 | grub2-tools | before 1:2.06-104.el9_6.alma.1 | 1:2.06-104.el9_6.alma.1 |
| AlmaLinux:9 | grub2-tools-efi | before 1:2.06-104.el9_6.alma.1 | 1:2.06-104.el9_6.alma.1 |
| AlmaLinux:9 | grub2-tools-extra | before 1:2.06-104.el9_6.alma.1 | 1:2.06-104.el9_6.alma.1 |
| AlmaLinux:9 | grub2-tools-minimal | before 1:2.06-104.el9_6.alma.1 | 1:2.06-104.el9_6.alma.1 |
| Debian:12 | grub2 | before 2.06-13+deb12u2 | 2.06-13+deb12u2 |
| Debian:13 | grub2 | before 2.12-6 | 2.12-6 |
| openSUSE:Tumbleweed | grub2 | before 2.12-35.1 | 2.12-35.1 |
| Red Hat:enterprise_linux:10.0 | grub2 | before 1:2.12-15.el10_0 | 1:2.12-15.el10_0 |
+56
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Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| almalinux:grub2-common | 1:2.12-15.el10_0.alma.1 · AlmaLinux:10 | Package registry (OSV) |
| almalinux:grub2-efi-aa64 | 1:2.06-104.el9_6.alma.1 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:grub2-efi-aa64-cdboot | 1:2.06-104.el9_6.alma.1 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:grub2-efi-aa64-modules | 1:2.12-15.el10_0.alma.1 · AlmaLinux:10 | Package registry (OSV) |
| almalinux:grub2-efi-x64 | 1:2.06-104.el9_6.alma.1 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:grub2-efi-x64-cdboot | 1:2.06-104.el9_6.alma.1 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:grub2-efi-x64-modules | 1:2.12-15.el10_0.alma.1 · AlmaLinux:10 | Package registry (OSV) |
| almalinux:grub2-pc | 1:2.06-104.el9_6.alma.1 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:grub2-pc-modules | 1:2.12-15.el10_0.alma.1 · AlmaLinux:10 | Package registry (OSV) |
| almalinux:grub2-ppc64le | 1:2.06-104.el9_6.alma.1 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:grub2-ppc64le-modules | 1:2.12-15.el10_0.alma.1 · AlmaLinux:10 | Package registry (OSV) |
| almalinux:grub2-tools | 1:2.06-104.el9_6.alma.1 · AlmaLinux:9 | Package registry (OSV) |
| debian:grub2 | 2.06-13+deb12u2 · Debian:12 | Package registry (OSV) |
| opensuse:grub2 | 2.12-150600.8.18.2 · openSUSE:Leap 15.6 | Package registry (OSV) |
| red hat:grub2 | 1:2.12-15.el10_0 · Red Hat:enterprise_linux:10.0 | Package registry (OSV) |
| red hat:grub2-common | 1:2.12-15.el10_0 · Red Hat:enterprise_linux:10.0 | Package registry (OSV) |
| red hat:grub2-debuginfo | 1:2.12-15.el10_0 · Red Hat:enterprise_linux:10.0 | Package registry (OSV) |
| red hat:grub2-debugsource | 1:2.12-15.el10_0 · Red Hat:enterprise_linux:10.0 | Package registry (OSV) |
| red hat:grub2-efi-aa64 | 1:2.12-15.el10_0 · Red Hat:enterprise_linux:10.0 | Package registry (OSV) |
| red hat:grub2-efi-aa64-cdboot | 1:2.12-15.el10_0 · Red Hat:enterprise_linux:10.0 | Package registry (OSV) |
| red hat:grub2-efi-aa64-modules | 1:2.12-15.el10_0 · Red Hat:enterprise_linux:10.0 | Package registry (OSV) |
| red hat:grub2-efi-x64 | 1:2.12-15.el10_0 · Red Hat:enterprise_linux:10.0 | Package registry (OSV) |
| red hat:grub2-efi-x64-cdboot | 1:2.12-15.el10_0 · Red Hat:enterprise_linux:10.0 | Package registry (OSV) |
| red hat:grub2-efi-x64-modules | 1:2.12-15.el10_0 · Red Hat:enterprise_linux:10.0 | Package registry (OSV) |
| red hat:grub2-emu-debuginfo | 1:2.12-15.el10_0 · Red Hat:enterprise_linux:10.0 | Package registry (OSV) |
| red hat:grub2-pc | 1:2.12-15.el10_0 · Red Hat:enterprise_linux:10.0 | Package registry (OSV) |
| rocky linux:grub2 | 1:2.12-15.el10_0 · Rocky Linux:10 | Package registry (OSV) |
| suse:grub2 | 2.04-150300.3.11.1 · SUSE:Linux Enterprise Micro 5.1 | Package registry (OSV) |
| suse:grub2 | 2.12-150600.8.18.2 · SUSE:Linux Enterprise Module for Basesystem 15 SP6 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2026-3842511 days apartQemu-kvm: hyperv/syndbg: missing mapped-length guard after cpu_physical_memory_map causes host oob write31Monitor
- CVE-2026-18220525 days apartBinutils: binutils: out-of-bounds write in bfd dlx elf backend relocation processing31Monitor
- CVE-2026-6507422 days apartDnsmasq: dnsmasq: denial of service due to out-of-bounds write in dhcp bootreply processing30Monitor
- CVE-2026-19387536 days apartGstreamer: gstreamer1-plugins-bad-free: gstreamer: heap out-of-bounds write in adpcmdec ima/dvi adpcm decoder30Monitor
- CVE-2026-59691505 days apartGstreamer1-plugins-bad-free: gstreamer: rfbsrc/librfb hextile heap out-of-bounds write with 16bpp framebuffer28Monitor
- CVE-2024-457761 days apartGrub2: grub-core/gettext: integer overflow leads to heap oob write and read.26Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
- CVE-2025-438279 days apartGrub2: grub allow access to encrypted device through cli once root device is unlocked via tpm23Monitor
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Someone with local access to the system can trigger it.
- Administrator privileges are required.
- No user action is required.
- Special conditions such as timing or configuration are required.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Local
- Attack complexity
- High
- Privileges required
- High
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-787 · Out-of-bounds WriteCVSS vector
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
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References
- access.redhat.com/errata/RHSA-2025:16154
- access.redhat.com/errata/RHSA-2025:6990
- access.redhat.com/security/cve/CVE-2025-0677
- bugzilla.redhat.com/show_bug.cgi?id=2346116
- lists.gnu.org/archive/html/grub-devel/2025-02/msg00024.html
Vendor advisories and official records. Exploit/PoC links are deliberately left out.