---
title: "CVE-2026-6507\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-2026-6507?format=md
keywords: index, follow
---

# CVE-2026-6507

Publication date 17 April 2026

Last updated 27 May 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-2026-6507?format=md#impact-score)

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## Description

A flaw was found in dnsmasq. A remote attacker could exploit an
out-of-bounds write vulnerability by sending a specially crafted BOOTREPLY
(Bootstrap Protocol Reply) packet to a dnsmasq server configured with the
`--dhcp-split-relay` option. This can lead to memory corruption, causing
the dnsmasq daemon to crash and resulting in a denial of service (DoS).

[Read the notes from the security team](https://ubuntu.com/security/CVE-2026-6507?format=md#notes)

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| dnsmasq | 26.04 LTS resolute | Fixed 2.92-1ubuntu0.3 |
| 25.10 questing | Not affected |
| 24.04 LTS noble | Not affected |
| 22.04 LTS jammy | 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)
* [Patch details](https://ubuntu.com/security/CVE-2026-6507?format=md#patch-details)

## Notes

---

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

introduced in 2.92test20 by:
https://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commitdiff;h=1677c6e10b81d4e1181e3a3f88e738ea6d69be8a

### 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 |
| --- | --- |
| dnsmasq | * Upstream:   <https://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commitdiff;h=9ad74926d4f7f34ff902e1db5235535aa813c33f> |

## 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-2026-6507)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2026-6507)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2026-6507)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2026-6507)

### Related Ubuntu Security Notices (USN)

+ [USN-8308-1](https://usn.ubuntu.com/USN-8308-1)
+ Dnsmasq vulnerability
+ 26 May 2026

### Other references

* <https://www.cve.org/CVERecord?id=CVE-2026-6507>
* <https://bugzilla.redhat.com/show_bug.cgi?id=2459181>