CVE-2021-3964

Name: CVE-2021-3964
Creator: NVD / NIST
Published: 2021-12-01T12:15:07.627+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.9/10EPSS 0.78%

Last modified Jun 17, 2026

CVE-2021-3964 is a medium-severity vulnerability rated 5.9/10 on the CVSS scale. elgg is vulnerable to Authorization Bypass Through User-Controlled Key. EPSS estimates a 0.78% chance of exploitation in the next 30 days.

Description

elgg is vulnerable to Authorization Bypass Through User-Controlled Key

Metrics

CVSS 3.1

5.9/10

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS Probability

0.78%

51.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-639

Affected Software

Vendor	Product	Versions
Elgg	Elgg	< 3.3.22

References

https://github.com/elgg/elgg/commit/d9fcad76ee380ea17edd61d13d0f87828ea3f744Patch, Third Party Advisory
https://huntr.dev/bounties/a4df45d6-b739-4299-967f-c960b569383aExploit, Patch, Third Party Advisory
https://github.com/elgg/elgg/commit/d9fcad76ee380ea17edd61d13d0f87828ea3f744Patch, Third Party Advisory
https://huntr.dev/bounties/a4df45d6-b739-4299-967f-c960b569383aExploit, Patch, Third Party Advisory

Timeline

Published: Dec 1, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-3964?

elgg is vulnerable to Authorization Bypass Through User-Controlled Key

How severe is CVE-2021-3964?

CVE-2021-3964 has a CVSS score of 5.9/10 (MEDIUM severity). The EPSS model estimates a 0.78% probability of exploitation in the next 30 days.

How do I fix CVE-2021-3964?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-3964?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST