# CVE-2026-126799: Gotenberg 8.31.0 before 8.38.0 SSRF via IPv6 Zone Identifiers in IsPublicIP

Status: published. Published: 2026-11-11. Updated: 2026-11-12.

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.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/gotenberg/gotenberg/commit/8e850b1c932452627fba397f2005dd6fd57b9617

## Affected products and versions

- gotenberg / gotenberg (github.com/gotenberg/gotenberg/v8): ≥ 8.31.0; < 8.38.0 (affected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 6.9 (medium); CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:H/SI:L/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:L/A:N; source: CNA: VulnCheck

- CVSS 4.0: 6.9 (medium); CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:H/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: disclosure@vulncheck.com

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:L/A:N; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: 0.42% as of 2026-11-12; percentile 37.03%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-918

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/gotenberg/gotenberg/security/advisories/GHSA-fqg9-x2xw-5crx (CNA: VulnCheck; vendor-advisory)

- https://github.com/gotenberg/gotenberg/commit/8e850b1c932452627fba397f2005dd6fd57b9617 (CNA: VulnCheck; patch)

- https://github.com/gotenberg/gotenberg/releases/tag/v8.38.0 (CNA: VulnCheck; release-notes)

- https://github.com/gotenberg/gotenberg/blob/v8.37.0/pkg/gotenberg/outbound.go#L112-L142 (CNA: VulnCheck; technical-description)

- https://www.vulncheck.com/advisories/gotenberg-8.31.0-before-8.38.0-ssrf-via-ipv6-zone-identifiers-in-ispublicip (CNA: VulnCheck; third-party-advisory)

- https://github.com/gotenberg/gotenberg/blob/v8.37.0/pkg/gotenberg/outbound.go#L112-L142 (disclosure@vulncheck.com)

- https://github.com/gotenberg/gotenberg/commit/8e850b1c932452627fba397f2005dd6fd57b9617 (disclosure@vulncheck.com)

- https://github.com/gotenberg/gotenberg/releases/tag/v8.38.0 (disclosure@vulncheck.com)

- https://github.com/gotenberg/gotenberg/security/advisories/GHSA-fqg9-x2xw-5crx (disclosure@vulncheck.com)

- https://www.vulncheck.com/advisories/gotenberg-8.31.0-before-8.38.0-ssrf-via-ipv6-zone-identifiers-in-ispublicip (disclosure@vulncheck.com)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-126799; retrieved 2026-11-12; source updated 2026-11-12

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-126799; retrieved 2026-11-12; source updated 2026-11-11

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-126799; retrieved 2026-11-12; source updated Not reported

Revision: b9ff20078d379114ac9c38f0bc67515430199a547554c89ef7fda649dd131e4c

Canonical: https://y2.dev/cve/CVE-2026-126799

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