CVE-2021-42567 json
Cross-site Scripting in Apereo CAS
published 2021-12-07 4 y ago modified 2026-06-17 4 mo ago also GHSA-gfhx-jjwq-63gv , EUVD-2021-2521
- cvss
- 6.1
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 8.2%
- EPSS 8.2% chance of exploitation in 30 days, percentile 94%
- public exploits
- 0
- none known, plus a Nuclei check
Summary
Apereo CAS through 6.4.1 allows XSS via POST requests sent to the REST API endpoints.
Patch / fix
- maven org.apereo.cas:cas-server-core-web 6.4.2
- apereo central_authentication_service 6.3.7.1, 6.4.2
- github.com/apereo/cas@376bf08 commit
- apereo.github.io/2021/10/18/restvuln/ advisory
Exploit prediction
8.19% chance of exploitation in the next 30 days, higher than 94% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- Nuclei template Apereo CAS Cross-Site Scripting nuclei detection template
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
| NVD | 2.0 | 4.3 | AV:N/AC:M/Au:N/C:N/I:P/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| maven | org.apereo.cas:cas-server-core-web | <6.4.2 |
6.4.2 |
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
References
-
apereo.github.io
/2021/10/18/restvuln/
patch, third-party-advisory
-
github.com
/apereo/cas/commit/376bf087d6d4267f61fc9f8028aa0d1ef407c3f0
web
-
github.com
/apereo/cas/releases
web, release-notes, third-party-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2021-42567
advisory
-
apereo.github.io
/2021/10/18/restvuln
web
-
github.com
/apereo/cas
package
Sources
- CVE List CVE-2021-42567
- GitHub Advisory GHSA-gfhx-jjwq-63gv
- NVD CVE-2021-42567
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