CVE-2026-38821: Buffer Overflow
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 httpmicrohttpd.c.
Affected Software
Event History
Frequently Asked Questions
Which deployments are exposed to this issue?
openNDS versions before 11.0.0 are affected. Exploitation requires the attacker to be on the captive portal network, so systems without attacker access to that network are not exposed through this described attack path.
Does an attacker need an account or user interaction to exploit it?
No. The vulnerability is described as exploitable by an unauthenticated attacker, and the vector indicates no user interaction is required. Exploitation is not described as low-complexity.
What is the expected impact of a successful exploit?
An attacker can crash the openNDS daemon, causing denial of service. The issue may also permit remote code execution, with high confidentiality and integrity impact indicated by the supplied severity vector.
What version should be used to remediate the issue?
Upgrade openNDS to version 11.0.0 or later. The affected code is identified as http_microhttpd.c, and the provided reference points to the associated upstream fix commit.