What’s Vulnerable › Vulnerabilities

CVE-2021-24591: Highlight < 0.9.3 - Authenticated Stored Cross-Site Scripting

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-09-06 · updated 2026-06-17
• Weakness: CWE-79

Description

The Highlight WordPress plugin before 0.9.3 does not sanitise its CustomCSS setting, allowing high privilege users to perform Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed

Affected products

• Highlight: before 0.9.3 — fixed in 0.9.3

How to fix

Upgrade to a fixed version: Highlight 0.9.3. Check the vendor advisory for mitigations.

References

• https://wpscan.com/vulnerability/c5cbe3b4-2829-4fd2-8194-4b3a2ae0e257
• https://wpscan.com/vulnerability/c5cbe3b4-2829-4fd2-8194-4b3a2ae0e257

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