What’s Vulnerable › Vulnerabilities

CVE-2020-27511

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.5% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-06-21 · updated 2026-06-17

Description

An issue was discovered in the stripTags and unescapeHTML components in Prototype 1.7.3 where an attacker can cause a Regular Expression Denial of Service (ReDOS) through stripping crafted HTML tags.

Affected products

• Prototypejs Prototype: 1.7.3

References

• http://prototypejs.org/
• https://github.com/prototypejs/prototype/blob/dee2f7d8611248abce81287e1be4156011953c90/src/prototype/lang/string.js#L283
• https://github.com/yetingli/PoCs/blob/main/CVE-2020-27511/Prototype.md
• http://prototypejs.org/
• https://github.com/prototypejs/prototype/blob/dee2f7d8611248abce81287e1be4156011953c90/src/prototype/lang/string.js#L283
• https://github.com/yetingli/PoCs/blob/main/CVE-2020-27511/Prototype.md

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