An issue was discovered in Joomla! before 3.9.15.
Priority LOW 29CWE-79Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Cross-site scripting
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-79.
Summary
An issue was discovered in Joomla! before 3.9.15. Inadequate escaping of usernames allows XSS attacks in com_actionlogs.
Why it matters now
EPSS 0.01015 63rd percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2020-8421
- 2026-10-03 Alias added: GHSA-m4hj-w5c6-qqv3
References
More Joomla! vulnerabilities
- TI-2016-08118 The mailSend function in the isMail transport in PHPMailer before 5.2.18 might allow… KEVCVSS 3.1CRITICAL 9.8
- TI-2017-06410 SQL injection vulnerability in Joomla! 3.7.x before 3.7.1 allows attackers to execute… CVSS 3.0CRITICAL 9.8
- TI-2016-08129 The isMail transport in PHPMailer before 5.2.20 might allow remote attackers to pass… CVSS 3.1CRITICAL 9.8
- TI-2016-07280 The register method in the UsersModelRegistration class in controllers/user.php in the… CVSS 3.0CRITICAL 9.8
- TI-2023-09555 [20230201] - Core - Improper access check in webservice endpoints KEVCVSS 3.1MEDIUM 5.3
- TI-2015-07045 Joomla! 1.5.x, 2.x, and 3.x before 3.4.6 allow remote attackers to conduct PHP object… CVSS 2.0HIGH 7.5
Sources
- CVE-2020-8421 · CVE Program
- CVE-2020-8421 · NVD
- FIRST EPSS
- GHSA-m4hj-w5c6-qqv3 · GitHub Advisory Database · CC BY 4.0
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