CVE-2026-5720: Miniupnp Project Miniupnpd

Critical severity, CVSS 9.1. EPSS: 1.1% chance of exploitation in the next 30 days.

miniupnpd contains an integer underflow vulnerability in SOAPAction header parsing that allows remote attackers to cause a denial of service or information disclosure by sending a malformed SOAPAction header with a single quote. Attackers can trigger an out-of-bounds memory read by exploiting improper length validation in ParseHttpHeaders(), where the parsed length underflows to a large unsigned value when passed to memchr(), causing the process to scan memory far beyond the allocated HTTP request buffer.

Affected products

• Miniupnp Project Miniupnpd: before 2.3.10 (fixed in 2.3.10)

Published 2026-04-17. Last modified 2026-06-29.