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Fencer Vulns
medium 6.1

CVE-2020-25828 json

MediaWiki Cross-site Scripting (XSS) vulnerability

published 2020-09-27 6 y ago modified 2026-06-17 4 mo ago also BIT-mediawiki-2020-25828 , EUVD-2022-4110 , GHSA-h8qx-mj6v-2934

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 65%
public exploits
0
none known

Summary

An issue was discovered in MediaWiki before 1.31.10 and 1.32.x through 1.34.x before 1.34.4. The non-jqueryMsg version of mw.message().parse() doesn't escape HTML. This affects both message contents (which are generally safe) and the parameters (which can be based on user input). (When jqueryMsg is loaded, it correctly accepts only whitelisted tags in message contents, and escapes all parameters. Situations with an unloaded jqueryMsg are rare in practice, but can for example occur for Special:SpecialPages on a wiki with no extensions installed.)

Patch / fix

  • packagist mediawiki/core 1.31.9, 1.34.3, 1.35.0
  • bitnami mediawiki 1.31.11, 1.34.4
  • mediawiki mediawiki 1.34.4
  • mediawiki Debian 14, Debian 13, Debian 12 1:1.35.0-1

debian advisories DEBIAN-CVE-2020-25828

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-2020-25828 updated cvss 6.1

mediawiki: non-jqueryMsg version of mw.message().parse() doesn't escape HTML leads to XSS

  • Red Hat OpenShift Container Platform 3.11 mediawiki Red Hat OpenShift Container Platform 4 mediawiki
    not affected: vulnerable code not present

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

1.09% chance of exploitation in the next 30 days, higher than 65% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
GitHub 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/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
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
packagist mediawiki/core
>=1.31.0, <1.31.9
>=1.32.0, <1.34.3
>=1.35.0-rc.0, <1.35.0
1.31.9
1.34.3
1.35.0
bitnami mediawiki
>=1.31.10, <1.31.11
>=1.32.0, <1.34.4
1.31.11
1.34.4

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.