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Ubuntu 26.04 LTS Dnsmasq Critical Service Disruption Vulnern 2026

Linuxsecurity •LinuxSecurity Advisories • May 26, 2026

A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 26.04 LTS Summary: Dnsmasq could be made to crash or run programs if it received specially crafted network traffic. Software Description: - dnsmasq: Small caching DNS proxy and DHCP/TFTP server Details: It was discovered that Dnsmasq incorrectly handled BOOTREPLY packets when configured with the --dhcp-split-relay option. A remote attacker could use this issue to cause Dnsmasq to crash, resulting in a denial of service, or possibly execute arbitrary code.

The problem can be corrected by updating your system to the following package versions: Ubuntu 26.04 LTS dnsmasq 2.92-1ubuntu0.3 In general, a standard system update will make all the necessary changes.

Ubuntu Security Notice USN-8308-1

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This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.

Critical Dnsmasq Vulnerability Exposes Ubuntu Systems to Remote Attacks A critical vulnerability in Dnsmasq affects Ubuntu 26.04 LTS and its derivatives, allowing remote attackers to crash the service or execute arbitrary code. The flaw arises from improper handling of BOOTREPLY packets when the --dhcp-split-relay option is enabled. This vulnerability can lead to denial of service and potential remote code execution. Users are advised to update their systems to the patched version dnsmasq 2.92-1ubuntu0.3. A standard system update will apply the necessary changes. The issue was disclosed on May 26, 2026, and impacts all systems running the affected versions of Dnsmasq. Ubuntu Pro offers extended security coverage for users managing multiple systems. 2 sources 72

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Ubuntu 26.04 LTS Dnsmasq Critical Service Disruption Vulnern 2026

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