What’s Vulnerable › Vulnerabilities

CVE-2021-28121

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.7% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-08-12 · updated 2026-06-17

Description

Virtual Robots.txt before 1.10 does not block HTML tags in the robots.txt field.

Affected products

• Virtual Robots.Txt Project Virtual Robots.Txt: before 1.10 — fixed in 1.10

How to fix

Upgrade to a fixed version: Virtual Robots.Txt Project Virtual Robots.Txt 1.10. Check the vendor advisory for mitigations.

References

• https://wordpress.org/plugins/pc-robotstxt/#developers
• https://wordpress.org/plugins/pc-robotstxt/#developers

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