High 7.8Published May 5, 2026

CVE-2026-40280Gotenberg SSRF via case-insensitive URL scheme bypass in webhook and downloadFrom deny-lists

Updated under an hour ago (Oct 26, 2026, 6:10 AM ET)

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Every CVE for gotenberg

Exploited in the last 30 days

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: 7.8 HIGH (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N
Weakness (CWE): CWE-918
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: May 6, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

gotenberg gotenberg gotenberg:gotenberg (from the name)	through 8.30.1	CNA record
thecodingmachine gotenberg thecodingmachine:gotenberg	before 8.31.0	NVD

References

https://github.com/gotenberg/gotenberg/security/advisories/GHSA-5q7p-7jgv-ww56x-refsource-confirm, exploit, mitigation, vendor-advisory
https://github.com/gotenberg/gotenberg/commit/3f01ca18d3cc21375a1e2da4b5a3f261c8548e47x-refsource-misc, patch
https://github.com/advisories/GHSA-jjwv-57xh-xr6rx-refsource-misc, not-applicable

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.