CVE-2020-8421
An issue was discovered in Joomla! before 3.9.15. Inadequate escaping of usernames allows XSS...
An issue was discovered in Joomla! before 3.9.15. Inadequate escaping of usernames allows XSS attacks in com_actionlogs.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
NVD Score used
An issue was discovered in Joomla! before 3.9.15. Inadequate escaping of usernames allows XSS attacks in com_actionlogs.
- Record
CVE-2020-8421- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - CVSS 2.0
- 4.3 Medium
AV:N/AC:M/Au:N/C:N/I:P/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
CVE List No score
An issue was discovered in Joomla! before 3.9.15. Inadequate escaping of usernames allows XSS attacks in com_actionlogs.
- Record
CVE-2020-8421- Updated
- 2026-11-02
EUVDEUVD-2020-29288 No score
An issue was discovered in Joomla! before 3.9.15. Inadequate escaping of usernames allows XSS attacks in com_actionlogs.
- Record
EUVD-2020-29288- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-m4hj-w5c6-qqv3 No score
An issue was discovered in Joomla! before 3.9.15. Inadequate escaping of usernames allows XSS...
An issue was discovered in Joomla! before 3.9.15. Inadequate escaping of usernames allows XSS attacks in com_actionlogs.
- Record
GHSA-m4hj-w5c6-qqv3- Updated
- 2026-11-02
OSV
An issue was discovered in Joomla! before 3.9.15. Inadequate escaping of usernames allows XSS attacks in com_actionlogs.
- Record
CVE-2020-8421- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Updated
- 2026-11-02
OSVBIT-joomla-2020-8421 No score
An issue was discovered in Joomla! before 3.9.15. Inadequate escaping of usernames allows XSS attacks in com_actionlogs.
- Record
BIT-joomla-2020-8421- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
joomlaBitnami |
3.9.0 up to 3.9.14 | 3.9.14 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2020-8421 is a medium vulnerability (CVSS 6.1) in Joomla Joomla\!, published January 28, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.01%, the 63rd percentile. Fixed in joomla 3.9.14.