CryptPad XSS via Link Bouncer before 2025.3.0
CVE-2025-49590 Published on June 18, 2025

CryptPad Dom-Based Cross-Site Scripting (XSS) Vulnerability
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.

NVD

Weakness Type

Incomplete Denylist to Cross-Site Scripting

The product uses a denylist-based protection mechanism to defend against XSS attacks, but the denylist is incomplete, allowing XSS variants to succeed. While XSS might seem simple to prevent, web browsers vary so widely in how they parse web pages, that a denylist cannot keep track of all the variations. The "XSS Cheat Sheet" [REF-714] contains a large number of attacks that are intended to bypass incomplete denylists.


Products Associated with CVE-2025-49590

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Affected Versions

cryptpad Version < 2025.3.0 is affected by CVE-2025-49590

Exploit Probability

EPSS
0.11%
Percentile
28.15%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.