CVE-2026-66824

critical

Description

A stored cross-site scripting vulnerability existed in the capture tree visualization page. The application embedded the serialized capture tree directly into an inline JavaScript block using the Jinja safe filter. Because the tree data can contain values derived from captured and potentially attacker-controlled web content, a specially crafted value could prematurely terminate the surrounding <script> element and inject arbitrary HTML or JavaScript. The malicious code would execute in the browser of a user viewing the affected capture tree. Successful exploitation could allow an attacker to perform actions using the victim’s authenticated session, access information available to the victim, or modify application data within the permissions of the affected user. The patch removes the JSON data from the HTML document and retrieves it through a dedicated API endpoint. The client then processes the response using response.json(), preventing capture data from being interpreted as executable content within the original page’s HTML or JavaScript context.

References

https://github.com/Lookyloo/lookyloo/commit/395187b57322ab311363ccc290c010b180389009

Details

Source: Mitre, NVD

Published: 2026-07-27

Updated: 2026-07-28

Risk Information

CVSS v2

Base Score: 3.5

Vector: CVSS2#AV:N/AC:M/Au:S/C:N/I:P/A:N

Severity: Low

CVSS v3

Base Score: 5.4

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Severity: Medium

CVSS v4

Base Score: 9.2

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:N/SC:H/SI:N/SA:N

Severity: Critical

EPSS

EPSS: 0.00277