CVE-2026-38821: Opennds

High severity, CVSS 7.1. EPSS: 0.3% chance of exploitation in the next 30 days.

A heap-based buffer overflow vulnerability exists in openNDS before 11.0.0 that allows an unauthenticated attacker on the captive portal network to crash the openNDS daemon (denial of service) and potentially achieve remote code execution. This is in http_microhttpd.c.

Affected products

• Opennds Opennds: before 11.0.0 (fixed in 11.0.0)

Published 2026-08-28. Last modified 2026-09-09.