What’s Vulnerable › Vulnerabilities

CVE-2021-42576

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.6% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-10-18 · updated 2026-06-17

Description

The bluemonday sanitizer before 1.0.16 for Go, and before 0.0.8 for Python (in pybluemonday), does not properly enforce policies associated with the SELECT, STYLE, and OPTION elements.

Affected products

• Microco Bluemonday: before 1.0.16 — fixed in 1.0.16
• Python Pybluemonday: before 0.0.8 — fixed in 0.0.8

How to fix

Upgrade to a fixed version: Microco Bluemonday 1.0.16; Python Pybluemonday 0.0.8. Check the vendor advisory for mitigations.

References

• https://docs.google.com/document/d/11SoX296sMS0XoQiQbpxc5pNxSdbJKDJkm5BDv0zrX50/
• https://docs.google.com/document/d/11SoX296sMS0XoQiQbpxc5pNxSdbJKDJkm5BDv0zrX50/

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