TemplateSandbox can be abused for XSS by asking another user to preview a page with a certain sandbox prefix

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-100376
StatePUBLISHED
Assignerwikimedia-foundation
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-25 21:17:21 UTC
Updated2026-09-25 21:17:21 UTC
DescriptionImproper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in Wikimedia Foundation Mediawiki - TemplateSandbox Extension allows Cross-Site Scripting (XSS). This issue affects Mediawiki - TemplateSandbox Extension: from * before 1.46.1, 1.45.5, 1.43.10.

Risk And Classification

Primary CVSS: v4.0 4.8 MEDIUM from c4f26cc8-17ff-4c99-b5e2-38fc1793eacc

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Problem Types: CWE-79 | CWE-79 CWE-79 Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting')

VersionSourceTypeScoreSeverityVector
4.0c4f26cc8-17ff-4c99-b5e2-38fc1793eaccSecondary4.8MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L/E:X/C...
4.0CNACVSS4.8MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
Low
User Interaction
Active
Confidentiality
Low
Integrity
Low
Availability
Low
Sub Conf.
Low
Sub Integrity
Low
Sub Availability
Low

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Wikimedia Foundation Mediawiki - TemplateSandbox Extension affected * 1.46.1, 1.45.5, 1.43.10 semver Not specified

References

ReferenceSourceLinkTags
phabricator.wikimedia.org/T430596 c4f26cc8-17ff-4c99-b5e2-38fc1793eacc phabricator.wikimedia.org
gerrit.wikimedia.org/r/q/I6630b9915f640bf75c8570165eb8728bd7a2c07a c4f26cc8-17ff-4c99-b5e2-38fc1793eacc gerrit.wikimedia.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: cookmeplox (en)

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