# CVE-2009-0845: Null dereference in n/a

> Remote attackers can crash the Kerberos daemon via a null pointer dereference in SPNEGO handling, requiring SPNEGO to be enabled.

- **Severity:** Medium 5.0 (`AV:N/AC:L/Au:N/C:N/I:N/A:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 27 Mar 2009
- **Updated:** 7 Aug 2024
- **Also known as:** DEBIAN-CVE-2009-0845, GHSA-74gr-5fw9-9jj5

## What is CVE-2009-0845?

CVE-2009-0845 is a medium-severity vulnerability in Mit Kerberos 5, published on 27 Mar 2009. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The spnego_gss_accept_sec_context function in lib/gssapi/spnego/spnego_mech.c in MIT Kerberos 5 (aka krb5) 1.5 through 1.6.3, when SPNEGO is used, allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via invalid ContextFlags data in the reqFlags field in a negTokenInit token.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2009-0845?

It affects 2 products.


Products: Mit Kerberos, Mit Kerberos 5.

## How do I fix CVE-2009-0845?

Upgrade to a fixed version.

## Is CVE-2009-0845 being exploited?

There is no known exploitation of CVE-2009-0845 in the wild and no public exploit code.

## Other vulnerabilities in Mit Kerberos 5

- [CVE-2009-4212](https://insights.sbomify.com/CVE-2009-4212/): Integer overflow in n/a (critical 10.0)
- [CVE-2004-0523](https://insights.sbomify.com/CVE-2004-0523/): Memory corruption in n/a (critical 10.0)
- [CVE-2010-0283](https://insights.sbomify.com/CVE-2010-0283/): Denial of service in n/a (high 7.8)
- [CVE-2018-5709](https://insights.sbomify.com/CVE-2018-5709/): Integer overflow in n/a (high 7.5)
- [CVE-2003-0138](https://insights.sbomify.com/CVE-2003-0138/): Auth bypass in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2009-0845 and fix it if it is affected.

What it is: CVE-2009-0845 is a medium-severity vulnerability in Mit Kerberos 5, published on 27 Mar 2009. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2009-0845 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-2009-0845/ (Markdown: https://insights.sbomify.com/CVE-2009-0845/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2009-0845
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2009-0845
- OSV: https://osv.dev/vulnerability/CVE-2009-0845

---
From sbomify Insights: https://insights.sbomify.com/CVE-2009-0845/
Summaries are generated and may contain mistakes; the official description above is the record.