Regex-Based Bypass Vulnerability in Gotenberg PDF API by Gotenberg
CVE-2026-42596

9.4CRITICAL

Key Information:

Vendor

Gotenberg

Status
Gotenberg
Vendor
CVE Published:
14 May 2026

What is CVE-2026-42596?

The Gotenberg PDF API, a Docker-powered tool for handling PDF files, has a vulnerability that allows attackers to bypass the default deny-lists in its downloadFrom and webhook features. This flaw occurs due to the regex-based and case-sensitive nature of the filter, enabling unauthenticated users to craft malicious URLs targeting internal loopback or private HTTP services that should have been protected. As a result, an external actor can make the server perform outbound requests to internal resources, thereby breaching otherwise secured boundaries. This issue was resolved in version 8.31.0.

Affected Version(s)

gotenberg < 8.31.0

References

https://github.com/gotenberg/gotenberg/security/advisorie...
x_refsource_CONFIRM

CVSS V3.1

Score:
9.4
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.