CVE-2026-19712Public exploitNetwork attack vector

Stored XSS via unescaped quiz description

Published Aug 16, 2026 · Updated Aug 16, 2026

Stored XSS in Masteriyo LMS before 2.3.3 allows remote authenticated users to execute scripts through a crafted quiz description. The plugin grants instructors unfiltered-HTML capability and outputs the quiz field without sanitization or escaping, causing saved markup to run when the affected page is viewed. Only default single-site installations are exposed; multisite sites and sites defining DISALLOW_UNFILTERED_HTML do not grant the required capability, and any visitor, including an administrator, can trigger the stored payload.

CVSS severity6.1
Medium
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Masteriyo LMS before 2.3.3 allows remote authenticated users to execute scripts through a crafted quiz description. The plugin grants instructors unfiltered-HTML capability and outputs the quiz field without sanitization or escaping, causing saved markup to run when the affected page is viewed. Only default single-site installations are exposed; multisite sites and sites defining DISALLOW_UNFILTERED_HTML do not grant the required capability, and any visitor, including an administrator, can trigger the stored payload.

The record

CVE
CVE-2026-19712
Published
Aug 16, 2026
Updated
Aug 16, 2026
Vendor
Query Solutions Ltd.
Product
Masteriyo LMS
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 16, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <2.3.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Query Solutions Ltd. · Masteriyo LMSversion=0 <2.3.3

Published CVSS scores

6.1CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007JavaScript/JScript

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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