# CVE-2016-3120: Null dereference in n/a

> Remote authenticated users can crash the Kerberos KDC via a null pointer dereference when restrict_anonymous_to_tgt is enabled.

- **Severity:** Medium 6.5 (`CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 1 Aug 2016
- **Updated:** 5 Aug 2024
- **Also known as:** ALPINE-CVE-2016-3120, DEBIAN-CVE-2016-3120, GHSA-8q8p-vxj6-fg2g, MGASA-2016-0306, SUSE-SU-2016:2136-1, UBUNTU-CVE-2016-3120

## What is CVE-2016-3120?

CVE-2016-3120 is a medium-severity vulnerability in Mit Kerberos 5, published on 1 Aug 2016. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

The validate_as_request function in kdc_util.c in the Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) before 1.13.6 and 1.4.x before 1.14.3, when restrict_anonymous_to_tgt is enabled, uses an incorrect client data structure, which allows remote authenticated users to cause a denial of service (NULL pointer dereference and daemon crash) via an S4U2Self request.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2016-3120?

It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `krb5` | SUSE:Linux Enterprise Desktop 12 SP1 | All versions | 1.12.1-36.4 |
| `krb5` | SUSE:Linux Enterprise Server 12 SP1 | All versions | 1.12.1-36.4 |
| `krb5` | SUSE:Linux Enterprise Server for SAP Applications 12 SP1 | All versions | 1.12.1-36.4 |
| `krb5` | SUSE:Linux Enterprise Software Development Kit 12 SP1 | All versions | 1.12.1-36.4 |

Products: Mit Kerberos 5.

## How do I fix CVE-2016-3120?

Upgrade to a fixed version.

## Is CVE-2016-3120 being exploited?

There is no known exploitation of CVE-2016-3120 in the wild and no public exploit code.

## Other vulnerabilities in Mit Kerberos 5

- [CVE-2011-0285](https://insights.sbomify.com/CVE-2011-0285/): Use after free in n/a (critical 10.0)
- [CVE-2008-0947](https://insights.sbomify.com/CVE-2008-0947/): Memory corruption in n/a (critical 10.0)
- [CVE-2007-5902](https://insights.sbomify.com/CVE-2007-5902/): Integer overflow in n/a (critical 10.0)
- [CVE-2007-4743](https://insights.sbomify.com/CVE-2007-4743/): Memory corruption in n/a (critical 10.0)
- [CVE-2007-3999](https://insights.sbomify.com/CVE-2007-3999/): Memory corruption in n/a (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-3120 and fix it if it is affected.

What it is: CVE-2016-3120 is a medium-severity vulnerability in Mit Kerberos 5, published on 1 Aug 2016. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2016-3120 in the wild and no public exploit code.

Affected product: Mit Kerberos 5. 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-2016-3120/ (Markdown: https://insights.sbomify.com/CVE-2016-3120/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-3120
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-3120
- OSV: https://osv.dev/vulnerability/CVE-2016-3120

---
From sbomify Insights: https://insights.sbomify.com/CVE-2016-3120/
Summaries are generated and may contain mistakes; the official description above is the record.