# CVE-2018-12540: High severity vulnerability that affects io.vertx:vertx-web

> Attackers can bypass CSRF protections in Eclipse Vert.x by replaying valid tokens, potentially allowing unauthorized actions on behalf of users.

- **Severity:** High 8.8 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 12 Jul 2018
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-rvgg-f8qm-6h7j

## What is CVE-2018-12540?

CVE-2018-12540 is a high-severity vulnerability in The Eclipse Foundation Eclipse Vert.x, published on 12 Jul 2018. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

In version from 3.0.0 to 3.5.2 of Eclipse Vert.x, the CSRFHandler do not assert that the XSRF Cookie matches the returned XSRF header/form parameter. This allows replay attacks with previously issued tokens which are not expired yet.

Weakness: CWE-352 (Cross-Site Request Forgery)

## Which versions are affected by CVE-2018-12540?

2 open source packages ship an affected version, including io.vertx:vertx-web. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `io.vertx:vertx-web` | Maven | From 3.0.0 | 3.5.3 |
| `io.vertx:vertx-web` | Maven | From 3.0.0 | 3.5.3 |

Products: Eclipse Vert.x.

## How do I fix CVE-2018-12540?

Upgrade io.vertx:vertx-web to 3.5.3 or later.

## Is CVE-2018-12540 being exploited?

There is no known exploitation of CVE-2018-12540 in the wild and no public exploit code.

Public exploit code:

- Vert.X CSRF Proof of Concept (CVE-2018-12540) (github_poc): https://github.com/bernard-wagner/vertx-web-xsrf
- https://github.com/tafamace/CVE-2018-12540 (github_poc): https://github.com/tafamace/CVE-2018-12540

## Other vulnerabilities in The Eclipse Foundation Eclipse Vert.x

- [CVE-2019-17640](https://insights.sbomify.com/CVE-2019-17640/): Path Traversal in Eclipse Vert (critical 9.8)
- [CVE-2018-12542](https://insights.sbomify.com/CVE-2018-12542/): Eclipse Vert.x does not properly neutralize '' (forward slashes) sequences that can resolve to an external location (critical 9.8)
- [CVE-2018-12544](https://insights.sbomify.com/CVE-2018-12544/): Moderate severity vulnerability that affects io.vertx:vertx-core (critical 9.8)
- [CVE-2026-102469](https://insights.sbomify.com/CVE-2026-102469/): Deserialization in Eclipse Vert.x (critical 9.2)
- [CVE-2026-102461](https://insights.sbomify.com/CVE-2026-102461/): Denial of service in Eclipse Vert.x (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-12540 and fix it if it is affected.

What it is: CVE-2018-12540 is a high-severity vulnerability in The Eclipse Foundation Eclipse Vert.x, published on 12 Jul 2018. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2018-12540 in the wild and no public exploit code.

Affected packages and fixed versions:
- io.vertx:vertx-web (Maven): affected from 3.0.0; fixed in 3.5.3
- io.vertx:vertx-web (Maven): affected from 3.0.0; fixed in 3.5.3

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2018-12540/ (Markdown: https://insights.sbomify.com/CVE-2018-12540/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-12540
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-12540
- OSV: https://osv.dev/vulnerability/CVE-2018-12540

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-12540/
Summaries are generated and may contain mistakes; the official description above is the record.