CVE-2020-8421 json
An issue was discovered in Joomla!
published 2020-01-28 6 y ago modified 2026-09-08 2 mo ago also BIT-joomla-2020-8421 , EUVD-2020-29288
- cvss
- 6.1
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.0%
- EPSS 1.0% chance of exploitation in 30 days, percentile 63%
- public exploits
- 0
- none known
Summary
An issue was discovered in Joomla! before 3.9.15. Inadequate escaping of usernames allows XSS attacks in com_actionlogs.
Patch / fix
- bitnami joomla 3.9.14
- joomla joomla! 3.9.14
Exploit prediction
1.01% chance of exploitation in the next 30 days, higher than 63% of all scored CVEs (FIRST EPSS, 2026-11-08).
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 |
| OSV | 3.1 | 6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| bitnami | joomla | >=3.9.0, <3.9.14 |
3.9.14 |
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
References
-
developer.joomla.org
/security-centre/800-20200103-core-xss-in-com-actionlogs
vendor-advisory, advisory
-
nvd.nist.gov
/vuln/detail/CVE-2020-8421
web
Sources
- CVE List CVE-2020-8421
- NVD CVE-2020-8421
- OSV BIT-joomla-2020-8421
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.