---
title: "CVE-2010-4021\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2010-4021?format=md
keywords: index, follow
---

# CVE-2010-4021

Publication date 2 December 2010

Last updated 24 July 2024

---

Ubuntu priority

**Medium**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

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## Description

The Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) 1.7 does not
properly restrict the use of TGT credentials for armoring TGS requests,
which might allow remote authenticated users to impersonate a client by
rewriting an inner request, aka a "KrbFastReq forgery issue."

[Read the notes from the security team](https://ubuntu.com/security/CVE-2010-4021?format=md#notes)

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| krb5 | 10.10 maverick | Not affected |
| 10.04 LTS lucid | Not affected |
| 9.10 karmic | Fixed 1.7dfsg~beta3-1ubuntu0.7 |
| 8.04 LTS hardy | Not affected |
| 6.06 LTS dapper | Not affected |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)
* [Patch details](https://ubuntu.com/security/CVE-2010-4021?format=md#patch-details)

## Notes

---

### [mdeslaur](https://launchpad.net/~mdeslaur)

1.7 only

### Patch details

For informational purposes only. We recommend not to cherry-pick updates. [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)

| Package | Patch details |
| --- | --- |
| krb5 | * Upstream:   <http://anonsvn.mit.edu/viewvc/krb5?view=revision&revision=23643> |

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2010-4021)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2010-4021)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2010-4021)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2010-4021)

### Related Ubuntu Security Notices (USN)

+ [USN-1030-1](https://usn.ubuntu.com/USN-1030-1)
+ Kerberos vulnerabilities
+ 9 December 2010

### Other references

* <http://web.mit.edu/kerberos/advisories/MITKRB5-SA-2010-007.txt>
* <https://www.cve.org/CVERecord?id=CVE-2010-4021>