---
title: "CVE-2021-25218\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-2021-25218?format=md
keywords: index, follow
---

# CVE-2021-25218

Publication date 18 August 2021

Last updated 25 August 2025

---

Ubuntu priority

**Medium**

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

## Cvss 3 Severity Score

**7.5 · High**

[Score breakdown](https://ubuntu.com/security/CVE-2021-25218?format=md#impact-score)

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## Description

In BIND 9.16.19, 9.17.16. Also, version 9.16.19-S1 of BIND Supported
Preview Edition When a vulnerable version of named receives a query under
the circumstances described above, the named process will terminate due to
a failed assertion check. The vulnerability affects only BIND 9 releases
9.16.19, 9.17.16, and release 9.16.19-S1 of the BIND Supported Preview
Edition.

[Read the notes from the security team](https://ubuntu.com/security/CVE-2021-25218?format=md#notes)

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| bind9 | 22.04 LTS jammy | Not affected |
| 21.10 impish | Not affected |
| 21.04 hirsute | Not affected |
| 20.04 LTS focal | Not affected |
| 18.04 LTS bionic | Not affected |
| 16.04 LTS xenial | Not affected |
| 14.04 LTS trusty | 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)

## Notes

---

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

Only affects version 9.16.19 so all current version in Ubuntu are not affected.

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

7.5 · High

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Network |
  | Attack complexity | Low |
  | Privileges required | None |
  | User interaction | None |
  | Scope | Unchanged |
  | Confidentiality impact | None |
  | Integrity impact | None |
  | Availability impact | High |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 7.5 · High |
  | Exploitability score | - |
  | Impact score | - |

**Vector:** CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-25218)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2021-25218)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2021-25218)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2021-25218)

### Other references

* <https://kb.isc.org/docs/cve-2021-25218>
* <https://www.openwall.com/lists/oss-security/2021/08/18/3>
* <https://www.cve.org/CVERecord?id=CVE-2021-25218>