CVE-2021-4072

Cross-site Scripting (XSS) - Stored in elgg/elgg

9.0 CriticalFix available

elgg is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: Low
User interaction: Required

What an attacker can affect

Confidentiality: High
Integrity: High
Availability: High

Exploit likelihood

0.72%Up 0.1 points since Dec 25, 2021

What each source reports

CVE List Score used 9.0

Cross-site Scripting (XSS) - Stored in elgg/elgg

elgg is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Record: CVE-2021-4072
CVSS 3.0: 9.0 CriticalCVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
Weakness: CWE-79
Updated: 2026-11-02

EUVDEUVD-2022-0429 9.0

elgg is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Record: EUVD-2022-0429
CVSS 3.0: 9.0 CriticalCVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
Updated: 2026-11-03

GitHub AdvisoriesGHSA-2xw8-j43j-5vxp 5.4

elgg is vulnerable to Cross-site Scripting

elgg is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Record: GHSA-2xw8-j43j-5vxp
CVSS 3.1: 5.4 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Weakness: CWE-79
Updated: 2026-11-02

NVD 5.4

elgg is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Record: CVE-2021-4072
CVSS 3.1: 5.4 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
CVSS 3.0: 9.0 CriticalCVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
CVSS 2.0: 3.5 LowAV:N/AC:M/Au:S/C:N/I:P/A:N
Weakness: CWE-79
Updated: 2026-11-02

OSV 5.4

elgg is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Record: CVE-2021-4072
CVSS 3.1: 5.4 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Updated: 2026-11-02

OSVGHSA-2xw8-j43j-5vxp 5.4

elgg is vulnerable to Cross-site Scripting

elgg is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Record: GHSA-2xw8-j43j-5vxp
CVSS 3.1: 5.4 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Weakness: CWE-79
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`elgg/elgg` Packagist	before 3.3.24	3.3.24
`elgg/elgg` Packagist	before 3.3.24, plus listed versions 1.10.01.10.0-rc.11.10.11.10.21.10.3 Show 45 moreShow less 1.10.41.10.51.10.61.11.01.11.11.11.21.11.31.11.41.11.51.11.61.12.01.12.11.12.101.12.111.12.121.12.131.12.141.12.151.12.161.12.171.12.181.12.21.12.31.12.41.12.51.12.61.12.71.12.81.12.91.9.01.9.0-rc.11.9.0-rc.21.9.0-rc.31.9.0-rc.41.9.0-rc.51.9.0-rc.61.9.0-rc.71.9.11.9.21.9.31.9.41.9.51.9.61.9.71.9.8	3.3.24

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-4072 is a critical vulnerability (CVSS 9.0) in Elgg, published December 24, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.72%, the 54th percentile. Fixed in elgg/elgg 3.3.24.

References

This page doesn't list everything

Left out here: 91 versions. The JSON record has them.