How severe is CVE-2021-32478?

CVE-2021-32478 has a CVSS score of 6.1/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2021-32478?

CVE-2021-32478 affects the following packages: moodle/moodle (Packagist), moodle/moodle (Packagist), moodle/moodle (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2021-32478?

Update moodle/moodle to 3.10.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-32478 is resolved across your whole dependency graph.

How do I detect CVE-2021-32478 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for moodle/moodle, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-32478 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2021-32478 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-32478 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-32478?

CVE-2021-32478 has an EPSS (Exploit Prediction Scoring System) score of 1.1%, placing it in the 65th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-32478?

CVE-2021-32478 is classified as Cross-site Scripting (XSS) (CWE-79), Open Redirect (CWE-601). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

Is there exploit tooling available for CVE-2021-32478?

A Nuclei detection template exists for CVE-2021-32478, meaning automated scanners can fingerprint it. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2021-32478 published, and has it been updated?

CVE-2021-32478 was published on March 11, 2022 and was last updated on July 9, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘

🐘 Packagist

Not in CISA KEV

MEDIUM severity

CVE-2021-32478 — moodle

MEDIUMFix: moodle/moodle@752ad3d

CVE-2021-32478 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in moodle/moodle. A fix is available for moodle/moodle — see the affected versions and patch details below.

Moodle reflected XSS

Also known asBIT-moodle-2021-32478GHSA-78fm-qhh8-8858

Published

Mar 11, 2022

Updated

Jul 9, 2026

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

Exploitation data as of Oct 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

1.1%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs65th percentile — riskier than 65% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-32478 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

3 pkgs affected

🐘moodle/moodle🐘moodle/moodle🐘moodle/moodle

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

The redirect URI in the LTI authorization endpoint required extra sanitizing to prevent reflected XSS and open redirect risks. Moodle versions 3.10 to 3.10.3, 3.9 to 3.9.6, 3.8 to 3.8.8 and earlier unsupported versions are affected.

Affected Packages

3 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`moodle/moodle`	≥ 3.10&&< 3.10.4	3.10.4`composer require moodle/moodle:^3.10.4`
🐘Packagist	`moodle/moodle`	≥ 3.9&&< 3.9.7	3.9.7`composer require moodle/moodle:^3.9.7`
🐘Packagist	`moodle/moodle`	≥ 3.8&&< 3.8.9	3.8.9`composer require moodle/moodle:^3.8.9`

Affected Products

1 product · 3 configurations

Application

moodlemoodle

≥ 3.10.0 && < 3.10.4

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for moodle/moodle, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update moodle/moodle to 3.10.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-32478 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

How to detect CVE-2021-32478

A community-maintained Nuclei template exists for this CVE. You can scan for it directly:

nuclei -id cve-2021-32478 -u https://target

Template: Moodle 3.8-3.10.3 - Reflected XSS & Open Redirect
Severity: medium
Impact: Attackers can inject malicious JavaScript or redirect users to malicious sites via insufficient sanitization in the redirect_uri parameter.
Remediation: Upgrade to Moodle version 3.8.9, 3.9.7, or 3.10.4 or later.

Template by ProjectDiscovery nuclei-templates (hackergautam), MIT licensed. View the full template. Scan only systems you are authorised to test.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2021-32478 in your dependencies?

Find it across Packagist, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

6.1/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Raw vector

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

CWE Classification

CWE-79Cross-site Scripting (XSS)CWE-601Open Redirect

Weaponization

OpenSSF Scorecard

Package health score

moodle

3.4/10

Code-Review0/10

Maintained10/10

Branch-Protection0/10

Assessed Oct 5, 2026

Timeline

Disclosed

Mar 11, 2022

Last updated

Jul 9, 2026

Identifiers

CVE-2021-32478

GHSA-78fm-qhh8-8858

BIT-moodle-2021-32478

References

Advisorynvd.nist.gov Fixmoodle.org Webgithub.com

Related vulnerabilities

This CVE is medium severity; 8 of 8 other CVEs affecting moodle/moodle are rated as high or higher (top: high).

CVE-2026-26047CVE-2026-26045CVE-2025-67853CVE-2025-67850CVE-2025-67857CVE-2025-67856CVE-2025-67848CVE-2025-67849

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedJul 9, 2026