CVE-2026-42592
MEDIUMCVE-2026-42592 is a medium-severity (CVSS 5.3) CWE-367 vulnerability in github.com/gotenberg/gotenberg/v8. O3 Security confirms whether CVE-2026-42592 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Gotenberg: DNS rebinding bypasses SSRF validation on Chromium URL conversion routes
Real-World Exposure
github.com/gotenberg/gotenberg/v8Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
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 Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/gotenberg/gotenberg/v8 | all versions | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/gotenberg/gotenberg/v8. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of github.com/gotenberg/gotenberg/v8 has shipped for CVE-2026-42592 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-42592 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-42592. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-42592 in your dependencies?
O3 detects CVE-2026-42592 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.