# CVE-2012-3520: Auth bypass in n/a

> Local attackers can spoof Netlink communications to bypass authentication checks in services like Avahi or NetworkManager.

- **Severity:** Low 1.9 (`AV:L/AC:M/Au:N/C:N/I:P/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 3 Oct 2012
- **Updated:** 6 Aug 2024
- **Also known as:** DEBIAN-CVE-2012-3520, GHSA-fxmm-x2w5-24cg

## What is CVE-2012-3520?

CVE-2012-3520 is a low-severity authentication bypass vulnerability in Linux kernel, published on 3 Oct 2012. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

The Netlink implementation in the Linux kernel before 3.2.30 does not properly handle messages that lack SCM_CREDENTIALS data, which might allow local users to spoof Netlink communication via a crafted message, as demonstrated by a message to (1) Avahi or (2) NetworkManager.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2012-3520?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2012-3520?

Upgrade to a fixed version.

## Is CVE-2012-3520 being exploited?

There is no known exploitation of CVE-2012-3520 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2012-3520 and fix it if it is affected.

What it is: CVE-2012-3520 is a low-severity authentication bypass vulnerability in Linux kernel, published on 3 Oct 2012. 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-2012-3520 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2012-3520/ (Markdown: https://insights.sbomify.com/CVE-2012-3520/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2012-3520
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2012-3520
- OSV: https://osv.dev/vulnerability/CVE-2012-3520

---
From sbomify Insights: https://insights.sbomify.com/CVE-2012-3520/
Summaries are generated and may contain mistakes; the official description above is the record.