CVE-2021-24559Public exploitNetwork attack vector

Stored XSS via unescaped QR-code data URI

Published Jan 16, 2024 · Updated Jun 20, 2025

Stored XSS in WP Chill Qyrr before 0.7 allows remote authenticated users to execute JavaScript through a crafted QR-code data URI. The data_uri_to_meta AJAX action accepts a contributor-supplied data-uri for arbitrary QR posts, and rendering places it in an image src attribute without output escaping. A contributor account and a nonce exposed on the QR post admin page are required; the script runs when another user views the embedded QR code.

CVSS severity5.4
Medium
EPSS probability0.22%
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 WP Chill Qyrr before 0.7 allows remote authenticated users to execute JavaScript through a crafted QR-code data URI. The data_uri_to_meta AJAX action accepts a contributor-supplied data-uri for arbitrary QR posts, and rendering places it in an image src attribute without output escaping. A contributor account and a nonce exposed on the QR post admin page are required; the script runs when another user views the embedded QR code.

The record

CVE
CVE-2021-24559
Published
Jan 16, 2024
Updated
Jun 20, 2025
Vendor
WP Chill
Product
Qyrr
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 16, 2024CVE publishedPublication date reported by the CVE source.
  2. Jun 20, 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 <0.7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

WP Chill · Qyrrversion=0 <0.7

Published CVSS scores

5.4CISA-ADPCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/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.

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 exploitPublished

Weakness, pattern, technique

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