# CVE-2026-6507: Dnsmasq: dnsmasq: denial of service due to out-of-bounds write in dhcp bootreply processing

CVE-2026-6507 is fixed in 8 products on 1 platform, first by dnsmasq 2.92-1ubuntu0.3, released April 17, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-6507
- Priority: High
- CVSS: 7.5 (Important)
- EPSS: 0.0048
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Apr 17, 2026
- Weakness: Out-of-bounds Write
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-6507

## 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).

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | dnsmasq Debian 14 | 2.92-4 | [DEBIAN-CVE-2026-6507](https://patchblox.com/security/data/fix/linux/debian-cve-2026-6507.md) | May 15, 2026 |
| Linux | dnsmasq Fedora 43 | 2.92rel2-2.fc43 | [FEDORA-2026-6384A3CF14](https://patchblox.com/security/data/fix/linux/fedora-2026-6384a3cf14.md) | May 12, 2026 |
| Linux | dnsmasq Ubuntu 26.04.1 LTS (resolute) | 2.92-1ubuntu0.3 | [dnsmasq 2.92-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-dnsmasq-2.92-1ubuntu0.3.md) | Apr 17, 2026 |
| Linux | dnsmasq opensuse-leap 16.0 | 2.93-160000.1.1 | [OPENSUSE-SU-2026:21192-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21192-1.md) | Jun 29, 2026 |
| Linux | dnsmasq sles 16.0 | 2.93-160000.1.1 | [SUSE-SU-2026:22496-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-22496-1.md) | Jun 29, 2026 |
| Linux | dnsmasq-base Ubuntu 26.04.1 LTS (resolute) | 2.92-1ubuntu0.3 | [dnsmasq-base 2.92-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-dnsmasq-base-2.92-1ubuntu0.3.md) | Apr 17, 2026 |
| Linux | dnsmasq-base-lua Ubuntu 26.04.1 LTS (resolute) | 2.92-1ubuntu0.3 | [dnsmasq-base-lua 2.92-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-dnsmasq-base-lua-2.92-1ubuntu0.3.md) | Apr 17, 2026 |
| Linux | dnsmasq-debuginfo Fedora 43 | 2.92rel2-2.fc43 | [FEDORA-2026-6384A3CF14](https://patchblox.com/security/data/fix/linux/fedora-2026-6384a3cf14.md) | May 12, 2026 |
| Linux | dnsmasq-debugsource Fedora 43 | 2.92rel2-2.fc43 | [FEDORA-2026-6384A3CF14](https://patchblox.com/security/data/fix/linux/fedora-2026-6384a3cf14.md) | May 12, 2026 |
| Linux | dnsmasq-langpack Fedora 43 | 2.92rel2-2.fc43 | [FEDORA-2026-6384A3CF14](https://patchblox.com/security/data/fix/linux/fedora-2026-6384a3cf14.md) | May 12, 2026 |
| Linux | dnsmasq-utils Fedora 43 | 2.92rel2-2.fc43 | [FEDORA-2026-6384A3CF14](https://patchblox.com/security/data/fix/linux/fedora-2026-6384a3cf14.md) | May 12, 2026 |
| Linux | dnsmasq-utils Ubuntu 26.04.1 LTS (resolute) | 2.92-1ubuntu0.3 | [dnsmasq-utils 2.92-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-dnsmasq-utils-2.92-1ubuntu0.3.md) | Apr 17, 2026 |
| Linux | dnsmasq-utils-debuginfo Fedora 43 | 2.92rel2-2.fc43 | [FEDORA-2026-6384A3CF14](https://patchblox.com/security/data/fix/linux/fedora-2026-6384a3cf14.md) | May 12, 2026 |

---

Data as of 2026-11-08T00:53:09Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.