TemplateSandbox can be abused for XSS by asking another user to preview a page with a certain sandbox prefix (CVE-2026-100376) | HOL Guard CVE

Medium · CVSS 4.8CVE-2026-100376

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

Answer in brief

CVE-2026-100376 records a Medium severity (CVSS 4.8) vulnerability in TemplateSandbox can be abused for XSS by asking another user to preview a page with a certain sandbox prefix. The current sources do not mark it as known exploited. The current feed maps Wikimedia Foundation/Mediawiki - TemplateSandbox Extension (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 25, 2026Updated Sep 25, 2026Source checked Sep 25, 2026First seen by HOL Sep 25, 2026Material review Sep 25, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 4.8
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 4.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Wikimedia Foundation/Mediawiki - TemplateSandbox Extension (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Wikimedia Foundation/Mediawiki - TemplateSandbox Extensiongeneric	>=* <1.46.1 1.45.5 1.43.10	1.46.1, 1.45.5, 1.43.10, 1.46.1

Recommended response

Check inventory. Check lockfiles and deployed manifests for Wikimedia Foundation/Mediawiki - TemplateSandbox Extension.
Review the reported fix. Update Wikimedia Foundation/Mediawiki - TemplateSandbox Extension to 1.46.1, 1.45.5, 1.43.10 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 25, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 25, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 25, 2026

Sources and claim methodology

Upstream source description

Improper 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.

Quoted source text, attributed separately from HOL analysis.