Vulnerability · Published May 14, 2026 · Assigned by GitHub_M
CVE-2026-42596Gotenberg: Unauthenticated SSRF via default deny-list bypass in downloadFrom and webhook
Critical 9.4
In plain English
A critical-severity server-side request forgery in gotenberg from gotenberg. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 1.6% (higher than 76% of all known vulnerabilities). Ready-made attack tooling exists: Nuclei. Fixed versions are available - upgrade the affected package.
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/gotenberg/gotenberg/v7 | no fix listed | GO-2026-5132 |
| Go | github.com/gotenberg/gotenberg/v8 | 8.32.0 | GHSA-4vmc-gm8v-m35h |
| Go | github.com/gotenberg/gotenberg/v8 | 8.32.0 | GO-2026-5132 |
Affected products (as reported)
Weakness: CWE-918 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L
References
- https://github.com/gotenberg/gotenberg/security/advisories/GHSA-4vmc-gm8v-m35h x_refsource_CONFIRM