What is CVE-2011-3621?

CVE-2011-3621 is a critical-severity vulnerability in Fluxbb. CVSS score: 9.8/10. Published 2020-01-22.

How severe is CVE-2011-3621?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Vulnerability in Fluxbb

CVE-2011-3621

A reverse proxy issue exists in FluxBB before 1.4.7 when FORUM_BEHIND_REVERSE_PROXY is enabled.

Published 2020-01-22 · last modified 2026-06-16.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.012 (66.9th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 67th percentile — 66.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.012 · newest: 0.012 · change: 0.000

Affected products

Fluxbb — versions before 1.4.7

References

www.openwall.com/lists/oss-security/2011/10/18/8 (Mailing List, Third Party Advisory)
fluxbb.org/forums/viewtopic.php (Vendor Advisory)

Frequently asked questions

What is CVE-2011-3621?: CVE-2011-3621 is a critical-severity vulnerability in Fluxbb. CVSS score: 9.8/10. Published 2020-01-22.
How severe is CVE-2011-3621?: Critical severity. CVSS v3 base score is 9.8 out of 10.