Critical (9.8) in eclipse vert.x. EPSS 2.0% chance of exploitation in the next 30 days. Fixed in io.vertx:vertx-web 3.9.4.
In Eclipse Vert.x 3.4.x up to 3.9.4, 4.0.0.milestone1, 4.0.0.milestone2, 4.0.0.milestone3, 4.0.0.milestone4, 4.0.0.milestone5, 4.0.0.Beta1, 4.0.0.Beta2, and 4.0.0.Beta3, StaticHandler doesn't correctly processes back slashes on Windows Operating systems, allowing, escape the webroot folder to the current working directory.
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
2.0% chance of exploitation in the next 30 days; higher than 80% of CVEs (scores of 2026-10-31)