# CVE-2010-4020: Weak cryptography in n/a

> Remote authenticated users can forge Kerberos signatures due to weak RC4 key derivation, potentially gaining privileges.

- **Severity:** Medium 6.3 (`CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L`)
- **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:** 2 Dec 2010
- **Updated:** 7 Aug 2024
- **Also known as:** DEBIAN-CVE-2010-4020, GHSA-27hw-qqm8-6prm

## What is CVE-2010-4020?

CVE-2010-4020 is a medium-severity vulnerability in Mit Kerberos 5, published on 2 Dec 2010. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

MIT Kerberos 5 (aka krb5) 1.8.x through 1.8.3 does not reject RC4 key-derivation checksums, which might allow remote authenticated users to forge a (1) AD-SIGNEDPATH or (2) AD-KDC-ISSUED signature, and possibly gain privileges, by leveraging the small key space that results from certain one-byte stream-cipher operations.

Weakness: CWE-310

## Which versions are affected by CVE-2010-4020?

It affects 1 product.


Products: Mit Kerberos 5.

## How do I fix CVE-2010-4020?

Apply the vendor's patch.

## Is CVE-2010-4020 being exploited?

There is no known exploitation of CVE-2010-4020 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-2010-4020 and fix it if it is affected.

What it is: CVE-2010-4020 is a medium-severity vulnerability in Mit Kerberos 5, published on 2 Dec 2010. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2010-4020 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-2010-4020/ (Markdown: https://insights.sbomify.com/CVE-2010-4020/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2010-4020
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2010-4020
- OSV: https://osv.dev/vulnerability/CVE-2010-4020

---
From sbomify Insights: https://insights.sbomify.com/CVE-2010-4020/
Summaries are generated and may contain mistakes; the official description above is the record.