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CVE-2026-40280

Thecodingmachine Gotenberg server-side request forgery (SSRF)

7.5 HIGHPublic exploitEPSS 2.11%
  1. Published5 May 2026

Description

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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityNone
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected products

Thecodingmachine Gotenberg< 8.31.0

Remediation

Fixed in
Thecodingmachine Gotenberg≥ 8.31.0

References

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Frequently asked

Is CVE-2026-40280 being actively exploited?

CVE-2026-40280 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 2.11%.

How severe is CVE-2026-40280?

CVE-2026-40280 has a CVSS 3.1 base score of 7.5, rated high. EPSS estimates a 2.11% probability of exploitation.

Which products are affected by CVE-2026-40280?

Affected products include Thecodingmachine Gotenberg.

How do I fix CVE-2026-40280?

Upgrade affected software to a fixed version, for example Thecodingmachine Gotenberg 8.31.0 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-40280 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.