CVE-2020-27620 json
The Cosmos Skin for MediaWiki through 1.35.0 has stored XSS because MediaWiki messages were not being properly escaped.
published 2020-10-22 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-20127
- cvss
- 6.1
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.1%
- EPSS 1.1% chance of exploitation in 30 days, percentile 66%
- public exploits
- 0
- none known
Summary
The Cosmos Skin for MediaWiki through 1.35.0 has stored XSS because MediaWiki messages were not being properly escaped. This is related to wfMessage and Html::rawElement, as demonstrated by CosmosSocialProfile::getUserGroups.
Exploit prediction
1.12% chance of exploitation in the next 30 days, higher than 66% 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 |
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
References
-
phabricator.wikimedia.org
/T265440
vendor-advisory
-
gerrit.wikimedia.org
/r/c/mediawiki/skins/Cosmos/+/634749
vendor-advisory
-
gerrit.wikimedia.org
/r/c/mediawiki/skins/Cosmos/+/634752
vendor-advisory
-
gerrit.wikimedia.org
/r/c/mediawiki/skins/Cosmos/+/634751
vendor-advisory
Sources
- CVE List CVE-2020-27620
- NVD CVE-2020-27620
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.