CVE-2025-43954Network attack vector

Cross-site scripting via unsafe heading token rendering

Published Apr 20, 2025 · Updated Apr 21, 2025

Cross-site scripting in Quasar Framework QMarkdown before 2.0.5 allows remote authenticated users to execute script via crafted headings. The extendHeading renderer replaces parsed heading children with an html_inline token containing their concatenated, unescaped label, bypassing no-html handling. Low-privileged access and control of rendered Markdown are required; successful exploitation runs attacker-controlled script in the page's browser context.

CVSS severity6.1
Medium
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Quasar Framework QMarkdown before 2.0.5 allows remote authenticated users to execute script via crafted headings. The extendHeading renderer replaces parsed heading children with an html_inline token containing their concatenated, unescaped label, bypassing no-html handling. Low-privileged access and control of rendered Markdown are required; successful exploitation runs attacker-controlled script in the page's browser context.

The record

CVE
CVE-2025-43954
Published
Apr 20, 2025
Updated
Apr 21, 2025
Vendor
Quasar Framework
Product
QMarkdown
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 20, 2025CVE publishedPublication date reported by the CVE source.
  2. Apr 21, 2025Record 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 <2.0.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Quasar Framework · QMarkdownversion=0 <2.0.5

Published CVSS scores

6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
4.9MITRECVSS:3.1/AV:N/AC:H/PR:L/UI:N/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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 exploitUnconfirmed

Weakness, pattern, technique

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

Public exploit references

No public exploit references are available in this record.

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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