# CVE-2026-126799: Gotenberg server-side request forgery in IsPublicIP IPv6 handling

Source: https://junglewise.ai/threats/cve-2026-126799-gotenberg-8-31-0-before-8-38-0-contains-a-server-side-request  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-11. Updated: 2026-11-11  
License: CC BY 4.0 with a link back

CVE-2026-126799 · Severity: high · CVSS 7.5 · Published 2026-11-11

Gotenberg, a document conversion service, fails to properly validate IPv6 addresses when classifying them as public or private. An attacker can exploit this by appending IPv6 zone identifiers (like %eth0) to internal IP addresses, bypassing the server's protections and reaching internal services through downloadFrom URLs, webhooks, or Chromium/LibreOffice conversion parameters, with responses leaked in generated PDFs.

Technologies: [Gotenberg](https://junglewise.ai/threats/technologies/gotenberg). Vendors: [Gotenberg](https://junglewise.ai/threats/vendors/gotenberg).

## Quick answers

**Is CVE-2026-126799 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-126799 being exploited in the wild.

**How severe is CVE-2026-126799?** High severity, with a CVSS score of 7.5, published 11 November 2026.

**Which products and versions are affected?** Gotenberg 8.31.0 before 8.38.0.

**Is there a fix for CVE-2026-126799?** Yes: fixed in 8.38.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-126799 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-126799?** Check whether you run Gotenberg at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 8.38.0

## Technical details

The IsPublicIP() function in outbound.go fails to strip IPv6 zone identifiers before checking against public IP deny-lists. An attacker can craft requests with URLs like http://[::1%eth0]/ or http://[::%1]/ to bypass private-IP protections and trigger server-side requests to internal services. The vulnerability affects versions 8.31.0 through 8.37.0 and requires no authentication.

## Affected products

- Gotenberg Gotenberg 8.31.0 before 8.38.0

## Timeline

- 2026-11-11: disclosed

## References

- [https://github.com/gotenberg/gotenberg/blob/v8.37.0/pkg/gotenberg/outbound.go](https://github.com/gotenberg/gotenberg/blob/v8.37.0/pkg/gotenberg/outbound.go)
- [https://github.com/gotenberg/gotenberg/commit/8e850b1c932452627fba397f2005dd6fd57b9617](https://github.com/gotenberg/gotenberg/commit/8e850b1c932452627fba397f2005dd6fd57b9617)

## Related threats

- [Gotenberg race condition in multipart downloadFrom handling](https://junglewise.ai/threats/cve-2026-45742-gotenberg-race-condition-in-multipart-downloadfrom-handling)
- [Gotenberg SSRF deny-list bypass in IsPublicIP via IPv6 prefixes](https://junglewise.ai/threats/cve-2026-45741-gotenberg-ssrf-deny-list-bypass-in-ispublicip-via-ipv6-prefixes)
- [Gotenberg path traversal via Windows-style separators in ZIP entry names](https://junglewise.ai/threats/cve-2026-44829-gotenberg-path-traversal-via-windows-style-separators-in-zip)
- [Gotenberg SSRF and local file disclosure in LibreOffice conversion](https://junglewise.ai/threats/cve-2026-55229-gotenberg-ssrf-and-local-file-disclosure-in-libreoffice)
- [Gotenberg SSRF and Information Disclosure in Chromium URL routes](https://junglewise.ai/threats/cve-2026-42597-gotenberg-ssrf-and-information-disclosure-in-chromium-url-routes)