CVE-2026-126799

Description

Gotenberg 8.31.0 before 8.38.0 contains a server-side request forgery vulnerability in IsPublicIP() that allows unauthenticated attackers to bypass private-IP deny-list protections using IPv6 zone identifiers. Attackers can append a zone such as %25eth0 to the unspecified address or blocked IPv6 prefixes in downloadFrom, webhook, or Chromium/LibreOffice URLs to reach internal services and read responses in the returned PDF.

References

• https://github.com/gotenberg/gotenberg/blob/v8.37.0/pkg/gotenberg/outbound.go#L112-L142
• https://github.com/gotenberg/gotenberg/commit/8e850b1c932452627fba397f2005dd6fd57b9617
• https://github.com/gotenberg/gotenberg/releases/tag/v8.38.0
• https://github.com/gotenberg/gotenberg/security/advisories/GHSA-fqg9-x2xw-5crx
• https://www.vulncheck.com/advisories/gotenberg-8.31.0-before-8.38.0-ssrf-via-ipv6-zone-identifiers-in-ispublicip