What is CVE-2021-43999?

CVE-2021-43999 is a high-severity vulnerability in Apache Guacamole, classified under Improper Authentication. CVSS score: 8.8/10. Published 2022-01-11.

How severe is CVE-2021-43999?

High severity. CVSS v3 base score is 8.8 out of 10.

Auth bypass in Apache Guacamole

CVE-2021-43999

Apache Guacamole 1.2.0 and 1.3.0 do not properly validate responses received from a SAML identity provider. If SAML support is enabled, this may allow a malicious user to assume the identity of another Guacamole user.

Vulnerability class: Broken Authentication

Published 2022-01-11 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.018 (77.4th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 77th percentile — 77.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.018 · newest: 0.018 · change: 0.000

Affected products

Apache Guacamole — versions 1.2.0, 1.3.0
Apache Software Foundation Guacamole — versions 1.3.0, 1.2.0

Weakness classification (CWE)

CWE-287 — Improper Authentication

References

lists.apache.org/thread/4dt9h5mo4o9rxlgxm3rp8wfqdtdjn2z9 (Mailing List, Vendor Advisory)
www.openwall.com/lists/oss-security/2022/01/11/7 (mailing-list, Mailing List, Third Party Advisory)

Frequently asked questions

What is CVE-2021-43999?: CVE-2021-43999 is a high-severity vulnerability in Apache Guacamole, classified under Improper Authentication. CVSS score: 8.8/10. Published 2022-01-11.
How severe is CVE-2021-43999?: High severity. CVSS v3 base score is 8.8 out of 10.