CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Called exploited 40 days after disclosure.
Measured from the CVE publication date to the earliest of 1 KEV catalogue that list it.
The life of this vulnerability
- CVE published
- First KEV listing40d
- Last sighting2mo
Gaps are compressed to equal steps. The elapsed time is printed under each.
Which catalogues call it exploited
- CISA KEVUS federaldoes not list it
- EUVDENISA, European Uniondoes not list it
- VulnCheck KEVcommercial researchlisted Jun 23, 2026
- CIRCLaggregator, mirrors the abovedoes not list it
This rests on a single catalogue. No second catalogue corroborates the claim that it is being exploited. CIRCL is an aggregator and is not counted.
Public exploitation evidence
- reported exploitationapi.vulncheck.com/v3/index/vulncheck-canaries?cve=CVE-2026-4
- reported exploitationapi.vulncheck.com/v3/index/vulncheck-canaries?cve=CVE-2026-4
- reported exploitationapi.vulncheck.com/v3/index/vulncheck-canaries?cve=CVE-2026-4
- reported exploitationapi.vulncheck.com/v3/index/vulncheck-canaries?cve=CVE-2026-4
- reported exploitationapi.vulncheck.com/v3/index/vulncheck-canaries?cve=CVE-2026-4
- reported exploitationapi.vulncheck.com/v3/index/vulncheck-canaries?cve=CVE-2026-4
42 public reports collected from VulnCheck and CIRCL, first on Jun 23, 2026. Each links to its original source. We have not verified them.
Description
Gotenberg is a Docker-powered stateless API for PDF files. Prior to 8.31.0, Gotenberg's /forms/pdfengines/metadata/write HTTP endpoint accepts a JSON metadata object and passes its keys directly to ExifTool via the go-exiftool library. No validation is performed on key characters. A \n embedded in a JSON key splits the ExifTool stdin stream into a new argument line, allowing an attacker to inject arbitrary ExifTool flags — including -if, which evaluates Perl expressions. This achieves unauthenticated OS command execution in a single HTTP request. The response is HTTP 200 with a valid PDF, making the attack transparent to basic monitoring. This vulnerability is fixed in 8.31.0.