CryptPad is a collaboration suite. Prior to version 2025.3.0, the "Link Bouncer" functionality attempts to filter javascript URIs to prevent Cross-Site Scripting (XSS), however this can be bypassed. There is an "early allow" code path that happens before the URI's protocol/scheme is checked, which a maliciously crafted URI can follow. This issue has been patched in version 2025.3.0.
Exploitability
AV:NAC:HAT:NPR:NUI:NVulnerable System
VC:NVI:NVA:NSubsequent System
SC:NSI:LSA:N2.9/CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N/E:POther