# CVE-2025-0677: Grub2: ufs: integer overflow may lead to heap based out-of-bounds write when handling symlinks

> An integer overflow in GRUB2's UFS module allows heap corruption and arbitrary code execution, enabling secure boot bypass via a malicious filesystem.

- **Severity:** Medium 6.4 (`CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 19 Feb 2025
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-56919, AZL-57007, BELL-CVE-2025-0677, CLSA-2026-1779370563, DEBIAN-CVE-2025-0677, GHSA-h592-gmp8-rvr7, UBUNTU-CVE-2025-0677

## What is CVE-2025-0677?

CVE-2025-0677 is a medium-severity vulnerability in Red Hat Enterprise Linux 10, published on 19 Feb 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2025-0677?


## How do I fix CVE-2025-0677?

Apply the vendor's patch.

## Is CVE-2025-0677 being exploited?

There is no known exploitation of CVE-2025-0677 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-0677 and fix it if it is affected.

What it is: CVE-2025-0677 is a medium-severity vulnerability in Red Hat Enterprise Linux 10, published on 19 Feb 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-0677 in the wild and no public exploit code.

Affected product: Red Hat Enterprise Linux 10. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-0677/ (Markdown: https://insights.sbomify.com/CVE-2025-0677/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-0677
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-0677
- OSV: https://osv.dev/vulnerability/CVE-2025-0677

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-0677/
Summaries are generated and may contain mistakes; the official description above is the record.