CVE-2020-5216: Twitter Secure Headers

Medium severity, CVSS 5.8. EPSS: 1.2% chance of exploitation in the next 30 days.

In Secure Headers (RubyGem secure_headers), a directive injection vulnerability is present in versions before 3.9.0, 5.2.0, and 6.3.0. If user-supplied input was passed into append/override_content_security_policy_directives, a newline could be injected leading to limited header injection. Upon seeing a newline in the header, rails will silently create a new Content-Security-Policy header with the remaining value of the original string. It will continue to create new headers for each newline. This has been fixed in 6.3.0, 5.2.0, and 3.9.0.

Affected products

• Twitter Secure Headers: before 3.9.0 (fixed in 3.9.0); from 5.0.0, before 5.2.0 (fixed in 5.2.0); from 6.0.0, before 6.3.0 (fixed in 6.3.0)

Published 2020-01-23. Last modified 2026-06-17.