How severe is CVE-2020-21487?

CVE-2020-21487 has a CVSS 3.x base score of 9.6, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2020-21487 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (47th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-21487?

CVE-2020-21487 primarily affects Netgate Pfsense. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-21487?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2020-21487 published?

CVE-2020-21487 was published on 2023-04-04 and last updated on 2026-06-17.

CVE-2020-21487

CVE-2020-21487 is a critical-severity vulnerability in Netgate Pfsense with a CVSS 3.x base score of 9.6. 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: Critical (CVSS 3.x base score 9.6)
EPSS exploit prediction: 1% (47th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Netgate Pfsense
Published: 2023-04-04
Last modified: 2026-06-17

Description

Cross Site Scripting vulnerability found in Netgate pfSense 2.4.4 and ACME package v.0.6.3 allows attackers to execute arbitrary code via the RootFolder field of acme_certificates.php.

Frequently asked questions

What is CVE-2020-21487?: Cross Site Scripting vulnerability found in Netgate pfSense 2.4.4 and ACME package v.0.6.3 allows attackers to execute arbitrary code via the RootFolder field of acme_certificates.php.
How severe is CVE-2020-21487?: CVE-2020-21487 has a CVSS 3.x base score of 9.6, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-21487 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (47th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-21487?: CVE-2020-21487 primarily affects Netgate Pfsense. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-21487?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2020-21487 published?: CVE-2020-21487 was published on 2023-04-04 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:netgate:pfsense:2.4.4:-:*:*:*:*:*:*
cpe:2.3:a:netgate:pfsense_acme_package:0.6.3:*:*:*:*:*:*:*

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CVE-2019-16915 — Critical (CVSS 9.8): An issue was discovered in pfSense through 2.4.4-p3. widgets/widgets/picture.widget.php uses the widgetkey parameter…
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