How severe is GHSA-gfhx-jjwq-63gv?

No CVSS score has been assigned to GHSA-gfhx-jjwq-63gv yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-gfhx-jjwq-63gv?

GHSA-gfhx-jjwq-63gv affects the following packages: org.apereo.cas:cas-server-core-web (Maven). Ecosystems affected: Maven.

How do I fix GHSA-gfhx-jjwq-63gv?

Update org.apereo.cas:cas-server-core-web to 6.4.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-gfhx-jjwq-63gv is resolved across your whole dependency graph.

How do I detect GHSA-gfhx-jjwq-63gv in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apereo.cas:cas-server-core-web, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-gfhx-jjwq-63gv 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 GHSA-gfhx-jjwq-63gv actively exploited in the wild?

No public exploit code has been indexed for GHSA-gfhx-jjwq-63gv 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 GHSA-gfhx-jjwq-63gv?

GHSA-gfhx-jjwq-63gv has an EPSS (Exploit Prediction Scoring System) score of 8.2%, placing it in the 95th 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 GHSA-gfhx-jjwq-63gv?

GHSA-gfhx-jjwq-63gv is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type 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 GHSA-gfhx-jjwq-63gv?

A Nuclei detection template exists for GHSA-gfhx-jjwq-63gv, 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 GHSA-gfhx-jjwq-63gv published, and has it been updated?

GHSA-gfhx-jjwq-63gv was published on December 10, 2021 and was last updated on November 30, 2024. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕ Maven

Not in CISA KEV

Cross-site Scripting in Apereo CASGHSA-gfhx-jjwq-63gv

Fix: apereo/cas@376bf08

GHSA-gfhx-jjwq-63gv is a Cross-site Scripting (XSS) vulnerability in org.apereo.cas:cas-server-core-web. A fix is available for org.apereo.cas:cas-server-core-web — see the affected versions and patch details below.

Also known asCVE-2021-42567

Published

Dec 10, 2021

Updated

Nov 30, 2024

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 11, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

8.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs95th percentile — riskier than 95% of all scored CVEsHighest risk

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

Real-World Exposure

1 pkg affected

☕org.apereo.cas:cas-server-core-web

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

Description

Apereo CAS through 6.4.1 allows XSS via POST requests sent to the REST API endpoints.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.apereo.cas:cas-server-core-web`	all versions	6.4.2`org.apereo.cas:cas-server-core-web:6.4.2`

Affected Products

1 product · 2 configurations

Application

central authentication serviceapereo

≥ 6.4.0 && < 6.4.2

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apereo.cas:cas-server-core-web, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.apereo.cas:cas-server-core-web to 6.4.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-gfhx-jjwq-63gv 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 GHSA-gfhx-jjwq-63gv

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

nuclei -id ghsa-gfhx-jjwq-63gv -u https://target

Template: Apereo CAS Cross-Site Scripting
Severity: medium
Impact: Successful exploitation of this vulnerability could allow an attacker to execute malicious scripts in the context of a victim's browser, potentially leading to session hijacking, data theft, or defacement.
Remediation: Apply the latest security patches or updates provided by the vendor to mitigate this vulnerability.

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

Frequently Asked Questions

Apereo CAS through 6.4.1 allows XSS via POST requests sent to the REST API endpoints.

O3 Security · Impact-Aware SCA

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