How severe is CVE-2021-4072?

CVE-2021-4072 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-4072 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (51st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-4072?

CVE-2021-4072 affects Elgg. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-4072?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-4072 published?

CVE-2021-4072 was published on 2021-12-24 and last updated on 2026-06-17.

CVE-2021-4072

CVE-2021-4072 is a medium-severity vulnerability in Elgg with a CVSS 3.x base score of 5.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 5.4)
CVSS v2: 3.5
EPSS exploit prediction: 1% (51st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Elgg
Published: 2021-12-24
Last modified: 2026-06-17

Description

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

Frequently asked questions

What is CVE-2021-4072?: elgg is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
How severe is CVE-2021-4072?: CVE-2021-4072 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-4072 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (51st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-4072?: CVE-2021-4072 affects Elgg. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-4072?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-4072 published?: CVE-2021-4072 was published on 2021-12-24 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:elgg:elgg:*:*:*:*:*:*:*:*

More vulnerabilities in Elgg

CVE-2011-2936 — Critical (CVSS 9.8): Elgg through 1.7.10 has a SQL injection vulnerability
CVE-2021-3980 — High (CVSS 7.5): elgg is vulnerable to Exposure of Private Personal Information to an Unauthorized Actor
CVE-2012-6562 — Medium (CVSS 6.8): engine/lib/users.php in Elgg before 1.8.5 does not properly specify permissions for the useradd action, which allows…
CVE-2011-2935 — Medium (CVSS 6.1): Elgg through 1.7.10 has XSS
CVE-2019-11016 — Medium (CVSS 6.1): Elgg before 1.12.18 and 2.3.x before 2.3.11 has an open redirect.
CVE-2021-3964 — Medium (CVSS 5.9): elgg is vulnerable to Authorization Bypass Through User-Controlled Key

All CVEs affecting Elgg →

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