CVE-2026-42596
CriticalExploitedPublic exploitGotenberg vulnerable to unauthenticated SSRF via default deny-list bypass in downloadFrom and webhook
Published May 7, 2026 · Updated Aug 12, 2026 · Also known as GHSA-4vmc-gm8v-m35h, GO-2026-5132
Key Facts
Patch immediately- CVE-2026-42596 is a critical-severity vulnerability (CVSS 9.4 v3.1) affecting Gotenberg (Thecodingmachine), github.com/gotenberg/gotenberg/v7 (go), github.com/gotenberg/gotenberg/v8 (go).
- It is exploited in the wild, listed in Industry KEV feed, CIRCL KEV since Oct 12, 2026. Public exploit code is available.
- EPSS estimates a 1.8% probability of exploitation in the next 30 days.
- Fixed versions are available, including github.com/gotenberg/gotenberg/v8 8.32.0, Gotenberg 8.31.0.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
9.4
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L
EPSS (30-day exploit likelihood)
1.8%
Higher than 77.8% of all scored CVEs
Exploited in the wild
Yes
2 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2026-42596 brief as a PDF
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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.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| Industry KEV feed | Oct 12, 2026 | n/a | Not reported |
| CIRCL KEV | Oct 12, 2026 | n/a | Not reported |
Required action: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.
Affected Products
4 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| GotenbergThecodingmachine | >= < 8.31.0 | 8.31.0 |
| github.com/gotenberg/gotenberg/v7go | See advisory | n/a |
| github.com/gotenberg/gotenberg/v8go | See advisory | 8.32.0 |
Patched Releases
github.com/gotenberg/gotenberg/v8
8.32.0
Gotenberg
8.31.0
Timeline
Publicly disclosed
May 7, 2026
Last updated
Aug 12, 2026
Added to Industry KEV feed
Oct 12, 2026
Added to CIRCL KEV
Oct 12, 2026
Weakness Type
- CWE-918 Server-Side Request Forgery (SSRF)
References
- advisoryGHSA advisory
- advisoryhttps://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42596.json
- advisoryhttps://nvd.nist.gov/vuln/detail/CVE-2026-42596
- exploitVulnCheck exploitation report
- articlehttps://github.com/gotenberg/gotenberg/security/advisories/GHSA-4vmc-gm8v-m35h
FAQ
Common Questions.
Gotenberg is a Docker-powered stateless API for PDF files.
Affected: Gotenberg (Thecodingmachine) versions >= < 8.31.0; github.com/gotenberg/gotenberg/v7 (go); github.com/gotenberg/gotenberg/v8 (go). The full list is in the CVE brief.
It is exploited in the wild, listed in Industry KEV feed, CIRCL KEV since Oct 12, 2026.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
Public exploit code is available.
Fixed versions are available, including github.com/gotenberg/gotenberg/v8 8.32.0, Gotenberg 8.31.0.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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