# CVE-2026-63334: draw.io: SSRF via DNS rebinding in ProxyServlet bypasses private IP blocklist

> Attackers can exploit DNS rebinding in the proxy feature to access internal services and cloud metadata, requiring the proxy feature to be enabled.

- **Severity:** Medium 6.8 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 21 Sep 2026
- **Updated:** 21 Sep 2026
- **Also known as:** GHSA-3v4h-8r2c-m8c5

## What is CVE-2026-63334?

CVE-2026-63334 is a medium-severity server-side request forgery vulnerability in jgraph drawio, published on 21 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

draw.io is a configurable diagramming and whiteboarding application. Prior to version 30.2.7, deployments with ENABLE_DRAWIO_PROXY=1 are vulnerable to server-side request forgery because src/main/java/com/mxgraph/online/Utils.java performs the private-address check in Utils.sanitizeUrl() using one DNS resolution, while src/main/java/com/mxgraph/online/ProxyServlet.java later calls URL.openConnection() and performs a second resolution. An attacker-controlled hostname can resolve to a public address during validation and then to a private, link-local, or cloud metadata address when the connection is opened. Successful exploitation can return cloud instance metadata or responses from internal HTTP services through the proxy. This issue is fixed in version 30.2.7.

Weakness: CWE-918 (Server-Side Request Forgery), CWE-367 (Time-of-check Time-of-use (TOCTOU) Race Condition)

## Which versions are affected by CVE-2026-63334?


## How do I fix CVE-2026-63334?

No fix has been published for CVE-2026-63334 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-63334 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-63334 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-63334 and fix it if it is affected.

What it is: CVE-2026-63334 is a medium-severity server-side request forgery vulnerability in jgraph drawio, published on 21 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-63334 exists.

Affected product: jgraph drawio. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-63334/ (Markdown: https://insights.sbomify.com/CVE-2026-63334/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-63334
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-63334
- OSV: https://osv.dev/vulnerability/CVE-2026-63334

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-63334/
Summaries are generated and may contain mistakes; the official description above is the record.