OpenVPN Access Server 2.9.0 through 2.9.4 allow remote attackers to inject arbitrary web script or HTML via the web login page URL.

published 2021-09-23 5y ago modified 2026-06-17 4mo ago also EUVD-2021-27073

cvss: 6.1; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.7%; EPSS 0.7% chance of exploitation in 30 days, percentile 55%
public exploits: 0; none known

Is CVE-2021-3824 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Exploit prediction

0.75% chance of exploitation in the next 30 days, higher than 55% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by	version	score	vector
NVD	3.1	6.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
NVD	2.0	4.3	AV:N/AC:M/Au:N/C:N/I:P/A:N

Affected products

n/a OpenVPN Access Server

Classification

Weakness

CWE-84 Improper Neutralization of Encoded URI Schemes in a Web Page
CWE-79 Improper Neutralization of Input During Web Page Generation

References

openvpn.net /vpn-server-resources/release-notes/#openvpn-access-server-2-9-5
release-notes, vendor-advisory

Sources

CVE List CVE-2021-3824
NVD CVE-2021-3824

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.