CVE-2026-35451: Twenty: Stored XSS via BlockNote FileBlock

Severity: medium (CVSS 5.7 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-04-21 · updated 2026-10-26
Weakness: CWE-79

Description

Twenty is an open source CRM. Prior to 1.20.6, a Stored Cross-Site Scripting (XSS) vulnerability exists in the BlockNote editor component. Due to a lack of protocol validation in the FileBlock component and insufficient server-side inspection of block content, an attacker can inject a javascript: URI into the url property of a file block. This allows the execution of arbitrary JavaScript when a user clicks on the malicious file attachment. This vulnerability is fixed in 1.20.6.

Affected products

twentyhq twenty: before 1.20.6

References

https://github.com/twentyhq/twenty/commit/8da69e0f77ea820a6845a4c3c025b6af3861d523
https://github.com/twentyhq/twenty/security/advisories/GHSA-7w89-7q26-gj7q
https://github.com/twentyhq/twenty/security/advisories/GHSA-7w89-7q26-gj7q

Get alerted when CVE-2026-35451 or the next vulnerability affects your stack