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CVE-2021-24559 - Before 0 Plugin

CVE-2021-24559

The Qyrr WordPress plugin before 0.7 does not escape the data-uri of the QR Code when outputting it in a src attribute, allowing for Cross-Site Scripting attacks. Furthermore, the data_uri_to_meta AJAX action, available to all authenticated users, only had a CSRF check in place, with the nonce available to users with a role as low as Contributor allowing any user with such role (and above) to set a malicious data-uri in arbitrary QR Code posts, leading to a Stored Cross-Site Scripting issue.

CVE-2021-24559

MEDIUM CVSS 5.4 Published 2024-01-16 Updated 2025-06-20
AI Risk Moderate (47/100) Active Exploit: No strong signal Published Exploit: No public exploit references Priority: P4 Planned
Severity Band MEDIUM
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Affected Components 2
Reference Links 1
AI Risk Engine Moderate (47/100)
Exploitability Low
Active Exploitation No strong signal
Published Exploit Status No public exploit references

Threat Timeline

  1. 2024-01-16 CVE published and first recorded in the threat feed.
  2. 2025-06-20 Record updated with latest vulnerability metadata.
  3. 2026-04-12 AI technical context refreshed for mitigation and impact guidance.
  4. Now Monitoring for follow-up changes, linked references, and new related CVEs.

AI Context

Machine-generated threat intelligence

AI Updated 4 days ago

AI enriched 4 days ago (2026-04-12 02:41 UTC)

Technical Summary

The Qyrr WordPress plugin before 0.7 does not escape the data-uri of the QR Code when outputting it in a src attribute, allowing for Cross-Site Scripting attacks. Furthermore, the data_uri_to_meta AJAX action, available to all authenticated users, only had a CSRF check in place, with the nonce available to users with a role as low as Contributor allowing any user with such role (and above) to set a malicious data-uri in arbitrary QR Code posts, leading to a Stored Cross-Site…

Potential Impact

Severity is MEDIUM (CVSS 5.4). Depending on deployment context, affected components may be exposed to unauthorized actions or data integrity risk.

Exploitability Assessment

Exploitability is assessed as Low based on severity and technical exposure profile.

Primary risk drivers: severity and technical exposure profile

Mitigation Recommendations

Validate affected product versions, prioritize patching, and monitor references for vendor remediation guidance. If immediate patching is not possible, apply compensating controls and limit exposure of vulnerable surfaces.

Detection & Monitoring

Track authentication anomalies, unexpected file writes, and suspicious plugin API activity around affected components.

Business Impact Lens

AI risk score 47/100 (Moderate, Low) with priority P4 Planned. Prioritize remediation where affected components process customer data, admin sessions, or Internet-exposed workflows.

Affected Products

Before 0 PLUGIN · before-0 Affected: < 0.7 Fixed in: 0.7
Qyrr PLUGIN · qyrr Affected: < 0.7 Fixed in: 0.7
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