# CVE-2026-6862: Efivar: efivar: denial of service due to stack overflow in device path node parsing

> A local attacker can cause a denial of service via stack overflow in the efivar library's device path parser due to missing length validation.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 22 Apr 2026
- **Updated:** 21 Sep 2026
- **Also known as:** DEBIAN-CVE-2026-6862, GHSA-364h-vxjm-52rp, OESA-2026-4450, RHSA-2026:69321, UBUNTU-CVE-2026-6862

## What is CVE-2026-6862?

CVE-2026-6862 is a medium-severity denial of service vulnerability in Red Hat Enterprise Linux 10, published on 22 Apr 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

A flaw was found in libefiboot, a component of efivar. The device path node parser in libefiboot fails to validate that each node's Length field is at least 4 bytes, which is the minimum size for an EFI (Extensible Firmware Interface) device path node header. A local user could exploit this vulnerability by providing a specially crafted device path node. This can lead to infinite recursion, causing stack exhaustion and a process crash, resulting in a denial of service (DoS).

Weakness: CWE-674 (Uncontrolled Recursion)

## Which versions are affected by CVE-2026-6862?

It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `efivar` | Red Hat:hummingbird:1 | All versions | 0:39-13.1.hum1 |
| `efivar-devel` | Red Hat:hummingbird:1 | All versions | 0:39-13.1.hum1 |
| `efivar-libs` | Red Hat:hummingbird:1 | All versions | 0:39-13.1.hum1 |

Products: Ubuntu Libefiboot.

## How do I fix CVE-2026-6862?

Apply the vendor's patch.

## Is CVE-2026-6862 being exploited?

There is no known exploitation of CVE-2026-6862 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-6862 and fix it if it is affected.

What it is: CVE-2026-6862 is a medium-severity denial of service vulnerability in Red Hat Enterprise Linux 10, published on 22 Apr 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-6862 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-2026-6862/ (Markdown: https://insights.sbomify.com/CVE-2026-6862/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-6862
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-6862
- OSV: https://osv.dev/vulnerability/CVE-2026-6862

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-6862/
Summaries are generated and may contain mistakes; the official description above is the record.