CVE-2026-42596 Gotenberg: Unauthenticated SSRF via default deny-list bypass in downloadFrom and webhook
An unauthenticated attacker can bypass default deny-lists to force the server to make requests to internal services, exposing private data.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-42596?
CVE-2026-42596 is a critical server-side request forgery vulnerability in gotenberg, published on 14 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Gotenberg is a Docker-powered stateless API for PDF files. Prior to 8.31.0, the default deny-lists used by Gotenberg's downloadFrom feature and webhook feature are bypassable. Because the filter is regex-based and case-sensitive, an unauthenticated attacker can supply URLs such as http://[::ffff:127.0.0.1]:... and reach loopback or private HTTP services that the default deny-list is intended to block. This crosses a real security boundary because an external caller can force the server to make outbound requests to internal-only targets. This vulnerability is fixed in 8.31.0.
Weakness: CWE-918
Which versions are affected by CVE-2026-42596?
4 open source packages ship an affected version, including github.com/gotenberg/gotenberg/v8 and github.com/gotenberg/gotenberg/v7. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/gotenberg/gotenberg/v8 Go | All versions | 8.32.0 |
github.com/gotenberg/gotenberg/v8 Go | All versions | 8.32.0 |
github.com/gotenberg/gotenberg/v8 Go | All versions | 8.32.0 |
github.com/gotenberg/gotenberg/v7 Go | All versions | None |
Products include Thecodingmachine Gotenberg.
How do I fix CVE-2026-42596?
Upgrade github.com/gotenberg/gotenberg/v8 to 8.32.0 or later.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-42596 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-42596 exists.
Public exploit code: 1 Nuclei template.
Other vulnerabilities in gotenberg
Sources
Also known as GHSA-4vmc-gm8v-m35h, GO-2026-5132.