Cyber Resilience

CVE-2026-40280

SSRF in Thecodingmachine Gotenberg ≤ 8.31.0

Public PoCSSRF
Published
05 May 2026
Modified
24 July 2026
Patch / advisory
CVSS Score v4 7.8
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/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
EPSS Score 0.0046 38th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-40280 is a high-severity SSRF (CWE-918) vulnerability in Thecodingmachine Gotenberg. Its CVSS base score is 7.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 38th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to AC-4 (Information Flow Enforcement) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1552.005 Cloud Instance Metadata API Credential Access
Adversaries may attempt to access the Cloud Instance Metadata API to collect credentials and other sensitive data.
Why these techniques?

SSRF bypass in public-facing API directly enables exploitation of the application (T1190) to reach and harvest credentials from cloud instance metadata endpoints (T1552.005).

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2026-42595Same product: Thecodingmachine Gotenberg
CVE-2026-39383Same product: Thecodingmachine Gotenberg
CVE-2026-42591Same product: Thecodingmachine Gotenberg
CVE-2026-42596Same product: Thecodingmachine Gotenberg
CVE-2026-42592Same product: Thecodingmachine Gotenberg
CVE-2026-27018Same product: Thecodingmachine Gotenberg
CVE-2026-42597Same product: Thecodingmachine Gotenberg
CVE-2026-42589Same product: Thecodingmachine Gotenberg
CVE-2026-42593Same product: Thecodingmachine Gotenberg
CVE-2026-42590Same product: Thecodingmachine Gotenberg

Affected Assets

thecodingmachine
gotenberg
≤ 8.31.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • SI-10 Information Input Validation
  • AC-4 Information Flow Enforcement
  • SC-7 Boundary Protection
Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V1.3.6
  • V1.5.3
  • V5.3.2
  • V10.4.7

Mitigating Controls (NIST 800-53 r5) AI

prevent

Directly requires rigorous validation and normalization of URL inputs (scheme, host) so that case-insensitive matching and private-IP deny-lists cannot be bypassed.

prevent

Enforces information-flow policies that block requests to private IP ranges and metadata endpoints regardless of URL encoding variations.

prevent

Boundary-protection mechanisms (egress filtering, deny-lists at the network layer) stop the application from reaching internal services even if the application-level check is evaded.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure development practices directly include input validation and destination allow-listing that prevent SSRF.

DE.CM-09 partial match
prevents

Runtime monitoring of web applications and services can detect anomalous outbound requests indicative of SSRF.

ID.RA-01 partial match
prevents

Vulnerability identification processes can discover and record SSRF flaws in web applications.

PR.IR-01 partial match
prevents

Network segmentation and egress controls can limit the damage from successful SSRF requests.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

prevents

Operational threat data describing SSRF campaigns can be used to tighten outbound-request allow-lists and detection rules before attackers exploit them.

References