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Exploitation reportedNot in CISA KEV yetFix available

CVE-2026-42596

Exploitation reported by one source. First attested on 2026-10-12 by GCVE · previdian.

  • Published2026-05-14
  • WeaknessCWE-918

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

Gotenberg is a Docker-powered stateless API for PDF files. Prior to 8.31.0, the default deny-lists used by Gotenberg's downloadFrom feature and webhook feature are bypassable. Because the filter is regex-based and case-sensitive, an unauthenticated attacker can supply URLs such as http://[::ffff:127.0.0.1]:... and reach loopback or private HTTP services that the default deny-list is intended to block. This crosses a real security boundary because an external caller can force the server to make outbound requests to internal-only targets. This vulnerability is fixed in 8.31.0.

Timeline

dates in UTC
  1. 2026-05-1416:16CVE publishedNVD
  2. 2026-10-1208:19Listed as exploited by GCVEGCVE
  3. 2026-10-1208:19Exploitation first reportedGCVE

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-42596?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-42596?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

OSV · NVD
gotenberg/gotenberg
BranchAffectedFixed in
—all versionsno fix published
gotenberg/gotenberg
BranchAffectedFixed in
8.32< 8.32.08.32.0
Thecodingmachine gotenberg
BranchAffectedFixed in
8.31< 8.31.08.31.0

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • NVDCVE recordread 2026-10-23
  • GCVEexploitation2026-10-12
  • CISA-ADPSSVC decisionpoc2026-05-15
  • OpenCVESSVC decisionpoc—
  • CNACVSS 3.19.4read 2026-10-23
  • CNAweakness (CWE)CWE-918read 2026-10-23
  • FIRST EPSSEPSS score1.8 %2026-10-23
  • OSVaffected packages—

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L
Published
2026-05-14
Last Modified
2026-06-17
NVD status
Analyzed

Frequently asked questions

What is CVE-2026-42596?

Gotenberg is a Docker-powered stateless API for PDF files. Prior to 8.31.0, the default deny-lists used by Gotenberg's downloadFrom feature and webhook feature are bypassable. Because the filter is regex-based and case-sensitive, an unauthenticated attacker can supply URLs such as http://[::ffff:127.0.0.1]:... and reach loopback or private HTTP services that the default deny-list is intended to block. This crosses a real security boundary because an external caller can force the server to make outbound requests to internal-only targets. This vulnerability is fixed in 8.31.0.

Is CVE-2026-42596 actively exploited?

A proof-of-concept exploit exists for CVE-2026-42596, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2026-42596?

CVE-2026-42596 has a CVSS v3 base score of 9.4 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L.

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