What’s Vulnerable › Vulnerabilities

CVE-2026-42596: Gotenberg: Unauthenticated SSRF via default deny-list bypass in downloadFrom and webhook

• Severity: critical (CVSS 9.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.6% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-05-14 · updated 2026-06-17
• Weakness: CWE-918

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 products

• gotenberg: before 8.31.0 — fixed in 8.31.0

How to fix

Upgrade to a fixed version: gotenberg 8.31.0. Check the vendor advisory for mitigations.

References

• https://github.com/gotenberg/gotenberg/security/advisories/GHSA-4vmc-gm8v-m35h
• https://github.com/gotenberg/gotenberg/security/advisories/GHSA-4vmc-gm8v-m35h

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