CVE-2026-42592: Gotenberg: DNS rebinding bypasses SSRF validation on Chromium URL conversion routes

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-05-14 · updated 2026-06-17
Weakness: CWE-367

Description

Gotenberg is a Docker-powered stateless API for PDF files. Prior to 8.32.0, FilterOutboundURL resolves the hostname, checks the resolved IPs against the private-address deny-list, and returns only the error. It discards the resolved addresses. Chromium later performs its own DNS resolution when it navigates to the URL. An attacker who controls DNS for a hostname with a short TTL returns a public IP on the first query (Gotenberg allows) and a private IP on the second query (Chromium connects to the attacker-chosen internal address). The CDP Fetch.requestPaused handler re-checks the URL but runs its own DNS resolution, leaving a timing window before Chromium's actual TCP connect. The rendered internal service response returns to the caller as a PDF. This vulnerability is fixed in 8.32.0.

Affected products

gotenberg: before 8.32.0 — fixed in 8.32.0

How to fix

Upgrade to a fixed version: gotenberg 8.32.0. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2026-42592 or the next vulnerability affects your stack