# CVE-2026-4893: CVE-2026-4893

CVE-2026-4893 is fixed in 7 products on 1 platform, first by dnsmasq 2.92-1ubuntu0.2, released May 11, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-4893
- Priority: High
- CVSS: 8.8 (Moderate)
- EPSS: 0.0178
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 9, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-4893

## Description

An information disclosure vulnerability in dnsmasq allows remote attackers to bypass source checks via a crafted DNS packet with RFC 7871 client subnet information.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | dnsmasq Debian 12.15 (bookworm) | 2.90-4~deb12u2 | [DEBIAN-CVE-2026-4893](https://patchblox.com/security/data/fix/linux/debian-cve-2026-4893.md) | May 15, 2026 |
| Linux | dnsmasq Debian 13.5 (trixie) | 2.91-1+deb13u1 | [DEBIAN-CVE-2026-4893](https://patchblox.com/security/data/fix/linux/debian-cve-2026-4893.md) | May 15, 2026 |
| Linux | dnsmasq Debian 14 | 2.92-5 | [DEBIAN-CVE-2026-4893](https://patchblox.com/security/data/fix/linux/debian-cve-2026-4893.md) | May 15, 2026 |
| Linux | dnsmasq RHEL 10 | 2.90-4.el10_0.1 | [RHSA-2026:92677](https://patchblox.com/security/data/fix/linux/rhsa-2026-92677.md) | May 27, 2026 |
| Linux | dnsmasq RHEL 8 | 0:2.79-36.el8_10 | [RHSA-2026:20589](https://patchblox.com/security/data/fix/linux/rhsa-2026-20589.md) | May 27, 2026 |
| Linux | dnsmasq RHEL 9 | 0:2.85-18.el9_8.1 | [RHSA-2026:19373](https://patchblox.com/security/data/fix/linux/rhsa-2026-19373.md) | May 27, 2026 |
| Linux | dnsmasq Ubuntu 18.04.6 LTS (bionic) | 2.90-0ubuntu0.18.04.1+esm3 | [dnsmasq 2.90-0ubuntu0.18.04.1+esm3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-dnsmasq-2.90-0ubuntu0.18.04.1-esm3.md) | May 27, 2026 |
| Linux | dnsmasq Ubuntu 20.04 LTS (focal) | 2.90-0ubuntu0.20.04.1+esm2 | [dnsmasq 2.90-0ubuntu0.20.04.1+esm2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-dnsmasq-2.90-0ubuntu0.20.04.1-esm2.md) | May 27, 2026 |
| Linux | dnsmasq Ubuntu 22.04.1 LTS (jammy) | 2.90-0ubuntu0.22.04.3 | [dnsmasq 2.90-0ubuntu0.22.04.3](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-dnsmasq-2.90-0ubuntu0.22.04.3.md) | May 27, 2026 |
| Linux | dnsmasq Ubuntu 24.04.5 LTS (noble) | 2.90-2ubuntu0.3 | [dnsmasq 2.90-2ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-noble-dnsmasq-2.90-2ubuntu0.3.md) | May 27, 2026 |
| Linux | dnsmasq Ubuntu 25.10 (questing) | 2.91-1ubuntu0.2 | [dnsmasq 2.91-1ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-questing-dnsmasq-2.91-1ubuntu0.2.md) | May 27, 2026 |
| Linux | dnsmasq Ubuntu 26.04.1 LTS (resolute) | 2.92-1ubuntu0.2 | [dnsmasq 2.92-1ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-dnsmasq-2.92-1ubuntu0.2.md) | May 11, 2026 |
| Linux | dnsmasq almalinux 10 | 2.90-7.el10_2 | [ALSA-2026:19158](https://patchblox.com/security/data/fix/linux/alsa-2026-19158.md) | May 19, 2026 |
| Linux | dnsmasq almalinux 8 | 2.79-36.el8_10 | [ALSA-2026:20589](https://patchblox.com/security/data/fix/linux/alsa-2026-20589.md) | May 26, 2026 |
| Linux | dnsmasq almalinux 9 | 2.85-18.el9_8.1 | [ALSA-2026:19373](https://patchblox.com/security/data/fix/linux/alsa-2026-19373.md) | May 19, 2026 |
| Linux | dnsmasq amzn 2023 | 2.90-1.amzn2023.0.3 | [ALAS2023-2026-1729](https://patchblox.com/security/data/fix/linux/alas2023-2026-1729.md) | May 25, 2026 |
| Linux | dnsmasq ol 10 | 0:2.90-7.el10_2 | [ELSA-2026-19158](https://patchblox.com/security/data/fix/linux/elsa-2026-19158.md) | Jul 16, 2026 |
| Linux | dnsmasq ol 8 | 0:2.79-36.el8_10 | [ELSA-2026-20589](https://patchblox.com/security/data/fix/linux/elsa-2026-20589.md) | May 26, 2026 |
| Linux | dnsmasq ol 9 | 0:2.85-18.el9_8.1 | [ELSA-2026-19373](https://patchblox.com/security/data/fix/linux/elsa-2026-19373.md) | Jun 23, 2026 |
| Linux | dnsmasq rocky 10 | 0:2.90-7.el10_2 | [RLSA-2026:19158](https://patchblox.com/security/data/fix/linux/rlsa-2026-19158.md) | May 29, 2026 |
| Linux | dnsmasq rocky 8 | 0:2.79-36.el8_10 | [RLSA-2026:20589](https://patchblox.com/security/data/fix/linux/rlsa-2026-20589.md) | May 29, 2026 |
| Linux | dnsmasq rocky 9 | 0:2.85-18.el9_8.1 | [RLSA-2026:19373](https://patchblox.com/security/data/fix/linux/rlsa-2026-19373.md) | May 28, 2026 |
| Linux | dnsmasq-base Ubuntu 18.04.6 LTS (bionic) | 2.90-0ubuntu0.18.04.1+esm3 | [dnsmasq-base 2.90-0ubuntu0.18.04.1+esm3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-dnsmasq-base-2.90-0ubuntu0.18.04.1-esm3.md) | May 27, 2026 |
| Linux | dnsmasq-base Ubuntu 20.04 LTS (focal) | 2.90-0ubuntu0.20.04.1+esm2 | [dnsmasq-base 2.90-0ubuntu0.20.04.1+esm2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-dnsmasq-base-2.90-0ubuntu0.20.04.1-esm2.md) | May 27, 2026 |
| Linux | dnsmasq-base Ubuntu 22.04.1 LTS (jammy) | 2.90-0ubuntu0.22.04.3 | [dnsmasq-base 2.90-0ubuntu0.22.04.3](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-dnsmasq-base-2.90-0ubuntu0.22.04.3.md) | May 27, 2026 |
| Linux | dnsmasq-base Ubuntu 24.04.5 LTS (noble) | 2.90-2ubuntu0.3 | [dnsmasq-base 2.90-2ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-noble-dnsmasq-base-2.90-2ubuntu0.3.md) | May 27, 2026 |
| Linux | dnsmasq-base Ubuntu 25.10 (questing) | 2.91-1ubuntu0.2 | [dnsmasq-base 2.91-1ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-questing-dnsmasq-base-2.91-1ubuntu0.2.md) | May 27, 2026 |
| Linux | dnsmasq-base Ubuntu 26.04.1 LTS (resolute) | 2.92-1ubuntu0.2 | [dnsmasq-base 2.92-1ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-dnsmasq-base-2.92-1ubuntu0.2.md) | May 11, 2026 |
| Linux | dnsmasq-base-lua Ubuntu 18.04.6 LTS (bionic) | 2.90-0ubuntu0.18.04.1+esm3 | [dnsmasq-base-lua 2.90-0ubuntu0.18.04.1+esm3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-dnsmasq-base-lua-2.90-0ubuntu0.18.04.1-esm3.md) | May 27, 2026 |
| Linux | dnsmasq-base-lua Ubuntu 20.04 LTS (focal) | 2.90-0ubuntu0.20.04.1+esm2 | [dnsmasq-base-lua 2.90-0ubuntu0.20.04.1+esm2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-dnsmasq-base-lua-2.90-0ubuntu0.20.04.1-esm2.md) | May 27, 2026 |
| Linux | dnsmasq-base-lua Ubuntu 22.04.1 LTS (jammy) | 2.90-0ubuntu0.22.04.3 | [dnsmasq-base-lua 2.90-0ubuntu0.22.04.3](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-dnsmasq-base-lua-2.90-0ubuntu0.22.04.3.md) | May 27, 2026 |
| Linux | dnsmasq-base-lua Ubuntu 24.04.5 LTS (noble) | 2.90-2ubuntu0.3 | [dnsmasq-base-lua 2.90-2ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-noble-dnsmasq-base-lua-2.90-2ubuntu0.3.md) | May 27, 2026 |
| Linux | dnsmasq-base-lua Ubuntu 25.10 (questing) | 2.91-1ubuntu0.2 | [dnsmasq-base-lua 2.91-1ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-questing-dnsmasq-base-lua-2.91-1ubuntu0.2.md) | May 27, 2026 |
| Linux | dnsmasq-base-lua Ubuntu 26.04.1 LTS (resolute) | 2.92-1ubuntu0.2 | [dnsmasq-base-lua 2.92-1ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-dnsmasq-base-lua-2.92-1ubuntu0.2.md) | May 11, 2026 |
| Linux | dnsmasq-debuginfo amzn 2023 | 2.90-1.amzn2023.0.3 | [ALAS2023-2026-1729](https://patchblox.com/security/data/fix/linux/alas2023-2026-1729.md) | May 25, 2026 |
| Linux | dnsmasq-debugsource amzn 2023 | 2.90-1.amzn2023.0.3 | [ALAS2023-2026-1729](https://patchblox.com/security/data/fix/linux/alas2023-2026-1729.md) | May 25, 2026 |
| Linux | dnsmasq-utils RHEL 8 | 0:2.79-36.el8_10 | [RHSA-2026:20589](https://patchblox.com/security/data/fix/linux/rhsa-2026-20589.md) | May 27, 2026 |
| Linux | dnsmasq-utils RHEL 9 | 0:2.85-18.el9_8.1 | [RHSA-2026:19373](https://patchblox.com/security/data/fix/linux/rhsa-2026-19373.md) | May 27, 2026 |
| Linux | dnsmasq-utils Ubuntu 18.04.6 LTS (bionic) | 2.90-0ubuntu0.18.04.1+esm3 | [dnsmasq-utils 2.90-0ubuntu0.18.04.1+esm3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-dnsmasq-utils-2.90-0ubuntu0.18.04.1-esm3.md) | May 27, 2026 |
| Linux | dnsmasq-utils Ubuntu 20.04 LTS (focal) | 2.90-0ubuntu0.20.04.1+esm2 | [dnsmasq-utils 2.90-0ubuntu0.20.04.1+esm2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-dnsmasq-utils-2.90-0ubuntu0.20.04.1-esm2.md) | May 27, 2026 |
| Linux | dnsmasq-utils Ubuntu 22.04.1 LTS (jammy) | 2.90-0ubuntu0.22.04.3 | [dnsmasq-utils 2.90-0ubuntu0.22.04.3](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-dnsmasq-utils-2.90-0ubuntu0.22.04.3.md) | May 27, 2026 |
| Linux | dnsmasq-utils Ubuntu 24.04.5 LTS (noble) | 2.90-2ubuntu0.3 | [dnsmasq-utils 2.90-2ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-noble-dnsmasq-utils-2.90-2ubuntu0.3.md) | May 27, 2026 |
| Linux | dnsmasq-utils Ubuntu 25.10 (questing) | 2.91-1ubuntu0.2 | [dnsmasq-utils 2.91-1ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-questing-dnsmasq-utils-2.91-1ubuntu0.2.md) | May 27, 2026 |
| Linux | dnsmasq-utils Ubuntu 26.04.1 LTS (resolute) | 2.92-1ubuntu0.2 | [dnsmasq-utils 2.92-1ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-dnsmasq-utils-2.92-1ubuntu0.2.md) | May 11, 2026 |
| Linux | dnsmasq-utils almalinux 10 | 2.90-7.el10_2 | [ALSA-2026:19158](https://patchblox.com/security/data/fix/linux/alsa-2026-19158.md) | May 19, 2026 |
| Linux | dnsmasq-utils almalinux 8 | 2.79-36.el8_10 | [ALSA-2026:20589](https://patchblox.com/security/data/fix/linux/alsa-2026-20589.md) | May 26, 2026 |
| Linux | dnsmasq-utils almalinux 9 | 2.85-18.el9_8.1 | [ALSA-2026:19373](https://patchblox.com/security/data/fix/linux/alsa-2026-19373.md) | May 19, 2026 |
| Linux | dnsmasq-utils amzn 2023 | 2.90-1.amzn2023.0.3 | [ALAS2023-2026-1729](https://patchblox.com/security/data/fix/linux/alas2023-2026-1729.md) | May 25, 2026 |
| Linux | dnsmasq-utils ol 10 | 0:2.90-7.el10_2 | [ELSA-2026-19158](https://patchblox.com/security/data/fix/linux/elsa-2026-19158.md) | Jul 16, 2026 |
| Linux | dnsmasq-utils ol 8 | 0:2.79-36.el8_10 | [ELSA-2026-20589](https://patchblox.com/security/data/fix/linux/elsa-2026-20589.md) | May 26, 2026 |
| Linux | dnsmasq-utils ol 9 | 0:2.85-18.el9_8.1 | [ELSA-2026-19373](https://patchblox.com/security/data/fix/linux/elsa-2026-19373.md) | Jun 23, 2026 |
| Linux | dnsmasq-utils-debuginfo amzn 2023 | 2.90-1.amzn2023.0.3 | [ALAS2023-2026-1729](https://patchblox.com/security/data/fix/linux/alas2023-2026-1729.md) | May 25, 2026 |

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