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Fencer Vulns
medium 6.1

CVE-2020-35474 json

In MediaWiki before 1.35.1, the combination of Html::rawElement and Message::text leads to XSS because the definition of MediaWiki:recentch…

published 2020-12-18 5 y ago modified 2026-06-17 4 mo ago also BIT-mediawiki-2020-35474 , EUVD-2020-23146

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 64%
public exploits
0
none known

Summary

In MediaWiki before 1.35.1, the combination of Html::rawElement and Message::text leads to XSS because the definition of MediaWiki:recentchanges-legend-watchlistexpiry can be changed onwiki so that the output is raw HTML.

Patch / fix

  • bitnami mediawiki 1.35.1
  • mediawiki mediawiki 1.35.1
  • mediawiki Debian 14, Debian 13, Debian 12 1:1.35.1-1

debian advisories DEBIAN-CVE-2020-35474

  • mediawiki Arch Linux 1.35.1-1

arch linux advisories AVG-1371

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-35474 updated cvss 6.1

mediawiki: message recentchanges-legend-watchlistexpiry can contain raw html

  • Red Hat OpenShift Container Platform 3.11 mediawiki
    affected: no fix planned “Will not fix”
  • Red Hat OpenShift Container Platform 4 mediawiki
    affected: no fix planned “Out of support scope”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.04% chance of exploitation in the next 30 days, higher than 64% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

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 mediawiki
<1.35.1
1.35.1

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

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.