# CVE-2021-35000: OpenBSD Kernel Multicast Routing Uninitialized Memory Information Disclosure Vulnerability

> Local attackers can disclose sensitive kernel memory via uninitialized data in multicast routing, potentially aiding privilege escalation.

- **Severity:** Low 3.3 (`CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 7 May 2024
- **Updated:** 18 Sep 2024
- **Also known as:** GHSA-rv7f-p2fx-hh7q

## What is CVE-2021-35000?

CVE-2021-35000 is a low-severity vulnerability in Openbsd Openbsd, published on 7 May 2024. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

OpenBSD Kernel Multicast Routing Uninitialized Memory Information Disclosure Vulnerability. This vulnerability allows local attackers to disclose sensitive information on affected installations of OpenBSD Kernel. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability.

The specific flaw exists within the implementation of multicast routing. The issue results from the lack of proper initialization of memory prior to accessing it. An attacker can leverage this in conjunction with other vulnerabilities to escalate privileges and execute arbitrary code in the context of the kernel.
. Was ZDI-CAN-16112.

Weakness: CWE-908 (Use of Uninitialized Resource)

## Which versions are affected by CVE-2021-35000?

It affects 1 product.


Products: Openbsd Openbsd.

## How do I fix CVE-2021-35000?

No fix has been published for CVE-2021-35000 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-35000 being exploited?

There is no known exploitation of CVE-2021-35000 in the wild and no public exploit code.

## Other vulnerabilities in Openbsd Openbsd

- [CVE-2007-1365](https://insights.sbomify.com/CVE-2007-1365/): Memory corruption in n/a (critical 10.0)
- [CVE-2004-0220](https://insights.sbomify.com/CVE-2004-0220/): Integer overflow in n/a (critical 10.0)
- [CVE-2004-0083](https://insights.sbomify.com/CVE-2004-0083/): Memory corruption in n/a (critical 10.0)
- [CVE-2004-0084](https://insights.sbomify.com/CVE-2004-0084/): Memory corruption in n/a (critical 10.0)
- [CVE-2001-0284](https://insights.sbomify.com/CVE-2001-0284/): Memory corruption in n/a (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-35000 and fix it if it is affected.

What it is: CVE-2021-35000 is a low-severity vulnerability in Openbsd Openbsd, published on 7 May 2024. 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-2021-35000 in the wild and no public exploit code.

Affected product: Openbsd Openbsd. 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-2021-35000/ (Markdown: https://insights.sbomify.com/CVE-2021-35000/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-35000
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-35000
- OSV: https://osv.dev/vulnerability/CVE-2021-35000

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-35000/
Summaries are generated and may contain mistakes; the official description above is the record.