CVE-2026-78221 Memory corruption in OpenVPN
Local authenticated users can trigger memory corruption or information disclosure in OpenVPN via crafted NRPT inputs due to incorrect buffer size calculation.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-78221?
CVE-2026-78221 is a medium-severity memory corruption vulnerability in OpenVPN, published on 7 Sep 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
An incorrect buffer size calculation in the Windows Interactive Service in OpenVPN 2.7_alpha1 through 2.7.6 allows local authenticated users to cause memory corruption or disclose sensitive information via crafted NRPT inputs.
Weakness: CWE-131
Which versions are affected by CVE-2026-78221?
How do I fix CVE-2026-78221?
No fix has been published for CVE-2026-78221 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-78221 being exploited?
There is no known exploitation of CVE-2026-78221 in the wild and no public exploit code.
Sources
Also known as GHSA-q6cg-7f58-2hwm.