CVE-2021-37634 – LeafKit allows XSS with untrusted user input

https://notcve.org/view.php?id=CVE-2021-37634

Leafkit is a templating language with Swift-inspired syntax. Versions prior to 1.3.0 are susceptible to Cross-site Scripting (XSS) attacks. This affects anyone passing unsanitised data to Leaf's variable tags. Before this fix, Leaf would not escape any strings passed to tags as variables. If an attacker managed to find a variable that was rendered with their unsanitised data, they could inject scripts into a generated Leaf page, which could enable XSS attacks if other mitigations such as a Content Security Policy were not enabled. • https://github.com/vapor/leaf-kit-ghsa-rv3x-xq3r-8j9h/pull/1 https://github.com/vapor/leaf-kit/security/advisories/GHSA-rv3x-xq3r-8j9h • CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') •