Cross-Site Request Forgery in Vert.x-Web framework

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.8 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS

• CVE-2020-35217: 0.59% estimated exploitation activity in the next 30 days; percentile 48.11 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Vert.x-Web framework v4.0 milestone 1-4 does not perform a correct CSRF verification. Instead of comparing the CSRF token in the request with the CSRF token in the cookie, it compares the CSRF token in the cookie against a CSRF token that is stored in the session. An attacker does not even need to provide a CSRF token in the request because the framework does not consider it. The cookies are automatically sent by the browser and the verification will always succeed, leading to a successful CSRF attack.

Published by the source

22 Apr 2021, 16:16 UTC

Last modified by the source

1 Feb 2023, 05:05 UTC

Source last checked

26 Oct 2026, 16:06 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-9q69-g5gc-9fgf

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2020-35217

Advisory: Cross-Site Request Forgery in Vert.x-Web framework
IDs: CVE-2020-35217, GHSA-9q69-g5gc-9fgf
Record: https://patchnext.com/advisories/cve-2020-35217 (revision 1, source checked 26 Oct 2026, 16:06 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: io.vertx:vertx-web 4.0.0-milestone5. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven io.vertx:vertx-web: affected >= 4.0.0-milestone1, <= 4.0.0-milestone1; >= 4.0.0-milestone2, <= 4.0.0-milestone2; >= 4.0.0-milestone3, <= 4.0.0-milestone3; >= 4.0.0-milestone4, <= 4.0.0-milestone4; fixed in 4.0.0-milestone5

## Suggested inspection (read-only)
- Maven io.vertx:vertx-web: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on io.vertx:vertx-web.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-9q69-g5gc-9fgf (GitHub-reviewed advisory GHSA-9q69-g5gc-9fgf lists affected ranges: Maven io.vertx:vertx-web >=4.0.0-milestone1 =4.0.0-milestone2 =4.0.0-milestone3 =4.0.0-milestone4 <=4.0.0-milestone4)

Commands are suggestions: review each one before running it.