Read the docs
TI-2026-29062 Aliases CVE-2026-40280GHSA-5q7p-7jgv-ww56

Gotenberg SSRF via case-insensitive URL scheme bypass in webhook and downloadFrom deny-lists

Priority HIGH 73CWE-918Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
None · None · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub.

Summary

Gotenberg is an API-based document conversion tool. In versions 8.30.1 and earlier, the default private-IP deny-lists for the --webhook-deny-list and --api-download-from-deny-list flags use a case-sensitive regular expression (^https?://) to match URL schemes. Because Go's net/url.Parse() normalizes the scheme to lowercase before establishing the outbound TCP connection, an attacker can bypass the deny-list by simply capitalizing part of the URL scheme (e.g., HTTP://, HTTPS://, or Http://). This allows unauthenticated requests to reach internal network services, including private IP ranges, loopback addresses, and cloud instance metadata endpoints such as HTTP://169.254.169.254/latest/meta-data/. This bypasses the same security control that was patched in CVE-2026-27018. This issue has been fixed in version 8.31.0.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.0195 80th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed github.com/gotenberg/gotenberg/v8 (Go): 8.31.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
gotenberggotenbergup to 8.30.1—No fix listedCNA
—github.com/gotenberg/gotenberg/v8 (Go)before 8.31.08.31.0Patch availableGHSA-5q7p-7jgv-ww56
  • gotenberg Vendorgotenberg Affected up to 8.30.1 Fixed in — No fix listed CNA
  • github.com/gotenberg/gotenberg/v8 (Go) Vendor— Affected before 8.31.0 Fixed in 8.31.0 Patch available GHSA-5q7p-7jgv-ww56

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:thecodingmachine:gotenberg:*:*:*:*:*:*:*:*before 8.31.0Vulnerablegotenberg
  • cpe:2.3:a:thecodingmachine:gotenberg:*:*:*:*:*:*:*:* Versions before 8.31.0 Vulnerable ·gotenberg

Remediation

  • Fix · GHSA-5q7p-7jgv-ww56 github.com/gotenberg/gotenberg/v8 (Go) Fixed in 8.31.0 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-40280
  2. 2026-10-03 Alias added: GHSA-5q7p-7jgv-ww56

References

Exploit 1

Patch 1

Advisory 2

Other 2

  • TI-2026-30869 Gotenberg: Unauthenticated RCE via ExifTool Metadata Key Injection CVSS 3.1CRITICAL 9.8
  • TI-2026-29063 Gotenberg vulnerable to argument injection via newlines in ExifTool metadata values CVSS 3.1CRITICAL 10.0
  • TI-2026-30876 Gotenberg: Unauthenticated SSRF via default deny-list bypass in downloadFrom and webhook CVSS 3.1CRITICAL 9.4
  • TI-2026-27588 Gotenberg has a ReDoS via extraHttpHeaders scope feature CVSS 4.0HIGH 8.7
  • TI-2026-30875 Gotenberg: Server-Side Request Forgery via Chromium URL Endpoint with Redirect-Based Deny-List Bypass CVSS 3.1HIGH 8.6
  • TI-2026-30871 Gotenberg: Server-Side Request Forgery (SSRF) in github.com/gotenberg/gotenberg/v8 CVSS 3.1HIGH 8.2
See all 21 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences