CVE-2026-42596
Gotenberg: Unauthenticated SSRF via default deny-list bypass in downloadFrom and webhook
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.
INFO
Published Date :
May 14, 2026, 4:16 p.m.
Last Modified :
May 18, 2026, 12:16 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | CRITICAL | [email protected] |
Solution
- Update Gotenberg to version 8.31.0 or later.
- Apply updated configuration for URL filtering.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-42596.
| URL | Resource |
|---|---|
| https://github.com/gotenberg/gotenberg/security/advisories/GHSA-4vmc-gm8v-m35h | Exploit Mitigation Vendor Advisory |
| https://github.com/gotenberg/gotenberg/security/advisories/GHSA-4vmc-gm8v-m35h | Exploit Mitigation Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-42596 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-42596
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-42596 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-42596 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
May. 18, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:thecodingmachine:gotenberg:*:*:*:*:*:*:*:* versions up to (excluding) 8.31.0 Added Reference Type CISA-ADP: https://github.com/gotenberg/gotenberg/security/advisories/GHSA-4vmc-gm8v-m35h Types: Exploit, Mitigation, Vendor Advisory Added Reference Type GitHub, Inc.: https://github.com/gotenberg/gotenberg/security/advisories/GHSA-4vmc-gm8v-m35h Types: Exploit, Mitigation, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
May. 15, 2026
Action Type Old Value New Value Added Reference https://github.com/gotenberg/gotenberg/security/advisories/GHSA-4vmc-gm8v-m35h -
New CVE Received by [email protected]
May. 14, 2026
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L Added CWE CWE-918 Added Reference https://github.com/gotenberg/gotenberg/security/advisories/GHSA-4vmc-gm8v-m35h