A Cascading Style Sheets (CSS) injection vulnerability in Swagger UI before 3.23.11 allows attackers to use the Relative Path Overwrite (RPO) technique to perform CSS-based input field value exfiltration, such as exfiltration of a CSRF token value. In other words, this product intentionally allows the embedding of untrusted JSON data from remote servers, but it was not previously known that <style>@import within the JSON data was a functional attack method.
Severity
CVSS 3.1
9.8 critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
5.7% chance of exploitation in the next 30 days; higher than 93% of CVEs (scores of 2026-10-31)