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Ubuntu MiniUPnPd Important Integer Underflow Denial Of Service Vuln 8731

Linuxsecurity •LinuxSecurity Advisories • September 7, 2026

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MiniUPnPd could be made to crash or expose sensitive information if it received specially crafted network traffic. Software Description: - miniupnpd: UPnP Internet Gateway Device Daemon Details: It was discovered that MiniUPnPd contained an integer underflow vulnerability in SOAPAction header parsing. A remote attacker could use this issue to cause a denial of service or information disclosure by sending a malformed SOAPAction header with a single quote.

MiniUPnPd could be made to crash or expose sensitive information if it

received specially crafted network traffic.

Software Description:

- miniupnpd: UPnP Internet Gateway Device Daemon

It was discovered that MiniUPnPd contained an integer underflow

vulnerability in SOAPAction header parsing. A remote attacker could

use this issue to cause a denial of service or information disclosure

by sending a malformed SOAPAction header with a single quote.

The problem can be corrected by updating your system to the following package versions: Ubuntu 26.04 LTS miniupnpd 2.3.9-2ubuntu0.1~esm1 Available with Ubuntu Pro miniupnpd-iptables 2.3.9-2ubuntu0.1~esm1 Available with Ubuntu Pro miniupnpd-nftables 2.3.9-2ubuntu0.1~esm1 Available with Ubuntu Pro Ubuntu 24.04 LTS miniupnpd 2.3.4-1ubuntu0.1~esm1 Available with Ubuntu Pro miniupnpd-iptables 2.3.4-1ubuntu0.1~esm1 Available with Ubuntu Pro miniupnpd-nftables 2.3.4-1ubuntu0.1~esm1 Available with Ubuntu Pro Ubuntu 22.04 LTS miniupnpd 2.2.3-1ubuntu0.1~esm1 Available with Ubuntu Pro miniupnpd-iptables 2.2.3-1ubuntu0.1~esm1 Available with Ubuntu Pro miniupnpd-nftables 2.2.3-1ubuntu0.1~esm1 Available with Ubuntu Pro Ubuntu 20.04 LTS miniupnpd 2.1-6.1ubuntu0.1~esm1 Available with Ubuntu Pro Ubuntu 18.04 LTS miniupnpd 2.0.20171212-2ubuntu0.1~esm1 Available with Ubuntu Pro Ubuntu 16.04 LTS miniupnpd 1.8.20140523-4.1+deb9u2ubuntu0.1~esm1 Available with Ubuntu Pro In general, a standard system update will make all the necessary changes.

Ubuntu Security Notice USN-8731-1

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Critical Integer Underflow Vulnerability in MiniUPnPd Affects Ubuntu Systems A significant integer underflow vulnerability has been identified in MiniUPnPd, affecting Ubuntu systems. This flaw allows remote attackers to exploit specially crafted SOAPAction headers to cause a denial of service or disclose sensitive information. The vulnerability is linked to the parsing of SOAPAction headers, where a single quote can trigger the issue. Systems running various versions of Ubuntu, including 20.04 LTS to 26.04 LTS, are impacted. Users are advised to update their systems to the latest package versions to mitigate the risk. The vulnerability has been assigned the identifier USN-8731-1. A standard system update will apply the necessary patches. The issue was disclosed on September 7, 2026, with no active exploitation reported yet. 2 sources 45

Extracted Entities

Ubuntu MiniUPnPd Important Integer Underflow Denial Of Service Vuln 8731

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Extracted Entities

Attack Types (2)

Companies (1)

CWE Weaknesses (1)

Platforms (1)

Vulnerabilities (1)