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Fencer Vulns
medium 5.4

CVE-2021-44855 json

An issue was discovered in MediaWiki before 1.35.5, 1.36.x before 1.36.3, and 1.37.x before 1.37.1.

published 2022-12-26 3 y ago modified 2026-06-17 4 mo ago also BIT-mediawiki-2021-44855 , EUVD-2021-31658

cvss
5.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 48%
public exploits
0
none known

Summary

An issue was discovered in MediaWiki before 1.35.5, 1.36.x before 1.36.3, and 1.37.x before 1.37.1. There is Blind Stored XSS via a URL to the Upload Image feature.

Patch / fix

  • bitnami mediawiki 1.35.5, 1.36.3, 1.37.1
  • mediawiki mediawiki 1.35.5, 1.36.3
  • mediawiki Debian 14, Debian 13, Debian 12 1:1.35.5-1

debian advisories DEBIAN-CVE-2021-44855

  • mediawiki Arch Linux 1.38.3-1

arch linux advisories AVG-2823

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-2021-44855 updated cvss 3.5

mediawiki: Blind Stored XSS via Upload Image via URL

  • Red Hat OpenShift Container Platform 3.11 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

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
18 mo ago

Exploit prediction

0.59% chance of exploitation in the next 30 days, higher than 48% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

CVSS scores

assigned by version score vector
CISA ADP 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
NVD 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
CNA 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
OSV 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
bitnami mediawiki
<1.35.5
>=1.36.0, <1.36.3
>=1.37.0, <1.37.1
1.35.5
1.36.3
1.37.1

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.