---
title: "CVE-2026-11331\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-2026-11331?format=md
keywords: index, follow
---

# CVE-2026-11331

Publication date 22 July 2026

Last updated 31 August 2026

---

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-2026-11331?format=md#impact-score)

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## Description

An attacker who knows (or guesses) that a resolver uses RPZ with wildcard
CNAME policies can craft query names long enough to trigger a NAMETOOLONG
error condition during RPZ processing. This is not handled correctly and
may lead to defeating the RPZ rule. It also may lead to an unexpected exit
of the BIND 9 software.
This issue affects BIND 9 versions 9.16.0 through 9.18.50, 9.20.0 through
9.20.24, 9.21.0 through 9.21.23, 9.16.8-S1 through 9.18.50-S1, and
9.20.9-S1 through 9.20.24-S1.

[Read the notes from the security team](https://ubuntu.com/security/CVE-2026-11331?format=md#notes)

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| bind9 | 26.04 LTS resolute | Fixed 1:9.20.24-1ubuntu0.2 |
| 24.04 LTS noble | Fixed 1:9.18.39-0ubuntu0.24.04.6 |
| 22.04 LTS jammy | Fixed 1:9.18.39-0ubuntu0.22.04.5 |
| 20.04 LTS focal | Needs evaluation |
| 18.04 LTS bionic | Needs evaluation |
| 16.04 LTS xenial | Needs evaluation |
| 14.04 LTS trusty | Needs evaluation |
| isc-dhcp | 26.04 LTS resolute | Needs evaluation |
| 24.04 LTS noble | Needs evaluation |
| 22.04 LTS jammy | Not affected |
| 20.04 LTS focal | Not affected |
| 18.04 LTS bionic | Needs evaluation |
| 16.04 LTS xenial | Not affected |
| 14.04 LTS trusty | Not affected |
| bind9-libs | 26.04 LTS resolute | Not in release |
| 24.04 LTS noble | Not in release |
| 22.04 LTS jammy | Needs evaluation |
| 20.04 LTS focal | Needs evaluation |

---

* [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)

As of isc-dhcp-4.4.3-1, isc-dhcp vendors bind9 libs

---

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

in focal and jammy, isc-dhcp uses the bind9-libs package
This is unlikely to affect isc-dhcp's use of bind9-libs and the
vendored bind9 libs, marking as negligible

## 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 | High |
  | Integrity impact | None |
  | Availability impact | None |
* 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:H/I:N/A:N

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-11331)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2026-11331)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2026-11331)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2026-11331)

### Related Ubuntu Security Notices (USN)

+ [USN-8648-1](https://usn.ubuntu.com/USN-8648-1)
+ Bind vulnerabilities
+ 19 August 2026

### Other references

* <https://www.cve.org/CVERecord?id=CVE-2026-11331>
* <https://kb.isc.org/docs/cve-2026-11331>