# CVE-2022-28735: Security feature bypass in GNU GRUB

> Attackers can bypass Secure Boot restrictions in GRUB2 to load unverified code, compromising system integrity on shim-powered systems.

- **Severity:** Medium 6.7 (`CVSS:3.1/AV:L/AC:L/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:** 20 Jul 2023
- **Updated:** 13 Feb 2025
- **Also known as:** AZL-27551, AZL-34790, DEBIAN-CVE-2022-28735, GHSA-w8wh-9mrg-3ff5, UBUNTU-CVE-2022-28735

## What is CVE-2022-28735?

CVE-2022-28735 is a medium-severity vulnerability in GNU GRUB, published on 20 Jul 2023. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

The GRUB2's shim_lock verifier allows non-kernel files to be loaded on shim-powered secure boot systems. Allowing such files to be loaded may lead to unverified code and modules to be loaded in GRUB2 breaking the secure boot trust-chain.

## Which versions are affected by CVE-2022-28735?

It affects 1 product.


Products: Gnu Grub2.

## How do I fix CVE-2022-28735?

Apply the vendor's patch.

## Is CVE-2022-28735 being exploited?

There is no known exploitation of CVE-2022-28735 in the wild and no public exploit code.

## Other vulnerabilities in GNU GRUB

- [CVE-2024-56737](https://insights.sbomify.com/CVE-2024-56737/): Memory corruption in GRUB2 (high 8.8)
- [CVE-2022-28733](https://insights.sbomify.com/CVE-2022-28733/): Integer underflow in grub_net_recv_ip4_packets (high 8.1)
- [CVE-2022-28734](https://insights.sbomify.com/CVE-2022-28734/): Out-of-bounds write when handling split HTTP headers (high 8.1)
- [CVE-2025-61662](https://insights.sbomify.com/CVE-2025-61662/): Grub2: missing unregister call for gettext command may lead to use-after-free (high 7.8)
- [CVE-2024-45782](https://insights.sbomify.com/CVE-2024-45782/): Grub2: fs/hfs: strcpy() using the volume name (fs/hfs.c:382) (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-28735 and fix it if it is affected.

What it is: CVE-2022-28735 is a medium-severity vulnerability in GNU GRUB, published on 20 Jul 2023. 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-2022-28735 in the wild and no public exploit code.

Affected product: GNU GRUB. 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-2022-28735/ (Markdown: https://insights.sbomify.com/CVE-2022-28735/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-28735
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-28735
- OSV: https://osv.dev/vulnerability/CVE-2022-28735

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-28735/
Summaries are generated and may contain mistakes; the official description above is the record.