CVE-2020-27511

7.5 highEPSS 3.3%

High (7.5) in prototypejs prototype. EPSS 3.3% chance of exploitation in the next 30 days.

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.

Severity

CVSS 3.1

7.5 high

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS: 3.3% chance of exploitation in the next 30 days; higher than 88% of CVEs (scores of 2026-10-31)
Published: 2021-06-21
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

prototypejs:prototype

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

Check your stack JSON