CVE-2026-21631: Joomla! Core - [20260303] - XSS vector in com_associations comparison view
Analyzed
Published 01-04-2026Last modified 02-04-2026
Vulnerability summary
CVE-2026-21631 is a medium (CVSS 5.9) Cross-site Scripting vulnerability in joomla! project joomla! cms. EPSS estimates a 0.22% chance of exploitation in the next 30 days, higher than 11.4% of scored vulnerabilities. 1 public exploit is recorded.
CVSS score
5.9/10
010
Medium · v4.0 (CVE.org)EPSS score
0.22%
0%100%
Low · 0.00 pp in 30 daysKEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits1github
Timeline
- 01-04-2026PublishedVulnerability first disclosed.
- 02-04-2026Last modifiedVulnerability information updated.
Description
Lack of output escaping leads to a XSS vector in the multilingual associations component.
CVSS metrics
3 scores · 2 sources · 2 versionsMedium 5.9Preferred score · CVE.org (CNA)
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/E:USourcesAll 2 agree
- NVDNIST5.9MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Medium 5.4Preferred score · NVD (NIST)
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:NSourcesSingle source
EPSS trend
Probability
0.22%
Chance of exploitation in the next 30 days
Percentile
11%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.22% on 22-09-2026
22-09-202622-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
1 foundSecurity Advisories
Maturity: poc
Weaknesses
CWE · root causeAffected systems
Joomla1 product
- joomla\!≥ 3.0.0, < 5.4.4 | ≥ 6.0.0, < 6.0.4
Joomla! project1 product
- joomla! cms4.0.0-5.4.3 | 6.0.0-6.0.3
2 vendors · 2 products
References
2 links- developer.joomla.org/security-centre/…Vendor Advisory