# CVE-2018-3968: Security feature bypass in Das U-Boot

> A local attacker can bypass U-Boot's verified boot protection to execute an unsigned kernel, compromising system integrity.

- **Severity:** High 8.2 (`CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:C/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:** 21 Mar 2019
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2018-3968, GHSA-xjmf-xr2j-gfx7

## What is CVE-2018-3968?

CVE-2018-3968 is a high-severity vulnerability in Das U-Boot, published on 21 Mar 2019. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

An exploitable vulnerability exists in the verified boot protection of the Das U-Boot from version 2013.07-rc1 to 2014.07-rc2. The affected versions lack proper FIT signature enforcement, which allows an attacker to bypass U-Boot's verified boot and execute an unsigned kernel, embedded in a legacy image format. To trigger this vulnerability, a local attacker needs to be able to supply the image to boot.

Weakness: CWE-347 (Improper Verification of Cryptographic Signature)

## Which versions are affected by CVE-2018-3968?

It affects 1 product.


Products: Denx U-Boot.

## How do I fix CVE-2018-3968?

Upgrade to a fixed version.

## Is CVE-2018-3968 being exploited?

There is no known exploitation of CVE-2018-3968 in the wild and no public exploit code.

## Other vulnerabilities in Das U-Boot

- [CVE-2022-34835](https://insights.sbomify.com/CVE-2022-34835/): Integer overflow in n/a (critical 9.8)
- [CVE-2022-30767](https://insights.sbomify.com/CVE-2022-30767/): Memory corruption in n/a (critical 9.8)
- [CVE-2020-8432](https://insights.sbomify.com/CVE-2020-8432/): Use after free in n/a (critical 9.8)
- [CVE-2019-14192](https://insights.sbomify.com/CVE-2019-14192/): Integer overflow in n/a (critical 9.8)
- [CVE-2019-14193](https://insights.sbomify.com/CVE-2019-14193/): Memory corruption in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-3968 and fix it if it is affected.

What it is: CVE-2018-3968 is a high-severity vulnerability in Das U-Boot, published on 21 Mar 2019. 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-2018-3968 in the wild and no public exploit code.

Affected product: Das U-Boot. 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-2018-3968/ (Markdown: https://insights.sbomify.com/CVE-2018-3968/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-3968
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-3968
- OSV: https://osv.dev/vulnerability/CVE-2018-3968

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-3968/
Summaries are generated and may contain mistakes; the official description above is the record.