CVE-2021-20187

Q: How do I fix CVE-2021-20187?

Upgrade moodle to 3.9.4 or later.

Q: Is CVE-2021-20187 being actively exploited?

Not that we know of. CVE-2021-20187 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 1.6% is the estimated probability that it will be exploited in the next 30 days. That is higher than 73% of all scored CVEs.

Q: How severe is CVE-2021-20187?

CVE-2021-20187 has a CVSS v3 base score of 7.2, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

Q: What does CVE-2021-20187 affect?

Published advisories record a fix for moodle (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

HIGHEPSS 73th pctl

7.2

CVSS v3

NVD

Description

It was found in Moodle before version 3.10.1, 3.9.4, 3.8.7 and 3.5.16 that it was possible for site administrators to execute arbitrary PHP scripts via a PHP include used during Shibboleth authentication.

CWE-94Code Injection CWE-829

How to fix

Remediation Available

moodleNVD

Affected:>= 3.9.0, < 3.9.4Fixed in:3.9.4CVE-2021-20187derived from NVD

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredHigh

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

1.57%probability of exploitation in 30 days

73rdpercentile

Elevated risk: more likely to be exploited than 73% of all known CVEs.

References

Patch1

moodle.org

Related Vulnerabilities

Other CWE-94 (Code Injection) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2017-9841	Critical	9.8	100%	KEV	Fix
CVE-2015-1635	Critical	9.8	100%	KEV	-
CVE-2025-3248	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2022-22954	Critical	9.8	100%	KEV + Ransom	-
CVE-2021-22204	Medium	6.8	100%	KEV	Fix
CVE-2012-0158	High	8.8	100%	KEV	-

Common questions

How do I fix CVE-2021-20187?

Upgrade moodle to 3.9.4 or later.

Is CVE-2021-20187 being actively exploited?

Not that we know of. CVE-2021-20187 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 1.6% is the estimated probability that it will be exploited in the next 30 days. That is higher than 73% of all scored CVEs.

How severe is CVE-2021-20187?

CVE-2021-20187 has a CVSS v3 base score of 7.2, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2021-20187 affect?

Published advisories record a fix for moodle (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

Embed a live status badge for CVE-2021-20187

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.