# CVE-2026-84790: OpenVPN identity impersonation via embedded NUL in certificate subject

Source: https://junglewise.ai/threats/cve-2026-84790-openvpn-2-7-alpha1-through-2-7-7-allows-remote-authenticated  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-13. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-84790 · Severity: info · Published 2026-10-13

OpenVPN is a widely-used VPN software that authenticates users and controls network access based on digital certificates. A vulnerability in versions 2.3.0 through 2.7.7 allows an already-authenticated attacker to impersonate other users by crafting a malicious certificate with an embedded NUL character in the subject field. This could allow an attacker to bypass identity checks and gain unauthorized access to resources intended for other users.

Technologies: [Openvpn](https://junglewise.ai/threats/technologies/openvpn). Vendors: [Openvpn](https://junglewise.ai/threats/vendors/openvpn).

## Quick answers

**Is CVE-2026-84790 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-84790 being exploited in the wild.

**How severe is CVE-2026-84790?** Informational severity, published 13 October 2026.

**Which products and versions are affected?** Openvpn 2.3.0 through 2.7.7.

**Is there a fix for CVE-2026-84790?** Yes: fixed in 2.7.8. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-84790 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-84790?** Check whether you run Openvpn at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 2.7.8

## Technical details

The vulnerability is an authentication bypass triggered by improper parsing of certificate subject fields containing embedded NUL bytes. An authenticated remote attacker can exploit this during the certificate validation process to impersonate other identities. The flaw affects OpenVPN 2.3.0 through 2.7.7 and is fixed in version 2.7.8.

## Affected products

- OpenVPN OpenVPN 2.3.0 through 2.7.7

## Timeline

- 2026-10-13: disclosed
- 2026-10-13: patched: Fixed in version 2.7.8

## References

- [https://community.openvpn.net/Security%20Announcements/CVE-2026-84790](https://community.openvpn.net/Security%20Announcements/CVE-2026-84790)

## Related threats

- [OpenVPN use-after-free in TLS session promotion or expiry](https://junglewise.ai/threats/cve-2026-84471-the-fix-for-was-incomplete-a-use-after-free-in-openvpn-2-6-0)
- [OpenVPN integer underflow in domain search options](https://junglewise.ai/threats/cve-2026-88964-an-integer-underflow-in-openvpn-version-2-7-alpha3-through-2-7-7)
- [OpenVPN ACK packet retransmission denial of service](https://junglewise.ai/threats/cve-2026-84732-openvpn-ack-packet-retransmission-denial-of-service)
- [OpenVPN argument parsing vulnerability on Windows](https://junglewise.ai/threats/cve-2026-84256-openvpn-argument-parsing-vulnerability-on-windows)
- [OpenVPN binary planting on Windows](https://junglewise.ai/threats/cve-2026-84226-openvpn-binary-planting-on-windows)