---
title: "CVE-2026-42596: Gotenberg vulnerable to unauthenticated SSRF via default deny-list bypass in downloadFrom and webhook"
url: https://erroneo.us/security/cve/CVE-2026-42596/
description: "CVE-2026-42596 (github.com/gotenberg/gotenberg/v8 (Go)): Gotenberg is a Docker-powered stateless API for PDF files. Prior to 8.31.0, the default deny-lists…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-05-14
date_modified: 2026-05-15
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-42596"
kev: false
cvss: 9.4
epss: 0.01773
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-42596: Gotenberg vulnerable to unauthenticated SSRF via default deny-list bypass in downloadFrom and webhook

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 1.8% , percentile 78: FIRST’s model estimates a 1.8% chance of exploitation activity in the next 30 days, higher than 78% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes github.com/gotenberg/gotenberg/v8 (Go) <= 8.30.1, fixed in 8.32.0 . Check your lockfile, including transitive dependencies.

## What it is

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

- Go `github.com/gotenberg/gotenberg/v8` <= 8.30.1 → fixed: 8.32.0

## Affected products (CVE record)

- gotenberg gotenberg: < 8.31.0

## Severity

- GitHub_M CVSS 3.1: 9.4 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L`
- GitHub CVSS 3.1: 9.4 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable yes , technical impact partial .
- FIRST EPSS (model of 2026-10-21): 1.77% probability of exploitation activity in the next 30 days; percentile 78.

## Sources

- [GitHub Advisory GHSA-4vmc-gm8v-m35h](https://github.com/advisories/GHSA-4vmc-gm8v-m35h)
- [CVE.org record CVE-2026-42596](https://www.cve.org/CVERecord?id=CVE-2026-42596)
- [NVD entry CVE-2026-42596](https://nvd.nist.gov/vuln/detail/CVE-2026-42596)
- [github.com](https://github.com/gotenberg/gotenberg/security/advisories/GHSA-4vmc-gm8v-m35h)

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Source page: https://erroneo.us/security/cve/CVE-2026-42596/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt