CVE-2021-39186 json
Improper Input Validation in GlobalNewFiles
published 2021-09-01 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-25576
- cvss
- 4.3
- version 3.1, CNA
- 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
GlobalNewFiles is a MediaWiki extension maintained by Miraheze. Prior to commit number cee254e1b158cdb0ddbea716b1d3edc31fa4fb5d, the username column of the GlobalNewFiles special page is vulnerable to a stored XSS. Commit number cee254e1b158cdb0ddbea716b1d3edc31fa4fb5d contains a patch. As a workaround, one may disallow <,> (or other characters required to insert html/js) from being used in account names so an XSS is not possible.
Patch / fix
Exploit prediction
1.01% chance of exploitation in the next 30 days, higher than 63% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- phabricator.miraheze.org https://phabricator.miraheze.org/T7935 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 4.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N |
| 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 |
Affected products
- miraheze GlobalNewFiles
Classification
- Weakness
-
- CWE-20 Improper Input Validation
References
-
github.com
/miraheze/GlobalNewFiles/commit/cee254e1b158cdb0ddbea716b1d3edc31fa4fb5d
patch, third-party-advisory
-
phabricator.miraheze.org
/T7935
exploit, third-party-advisory
-
github.com
/miraheze/GlobalNewFiles/security/advisories/GHSA-57p5-hqjq-h7vg
third-party-advisory
Sources
- CVE List CVE-2021-39186
- NVD CVE-2021-39186
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.