Gotenberg: Path traversal in zip entry name via Windows-style separators in upload filename

Gotenberg is a Docker-powered stateless API for PDF files. In 8.32.0 and earlier, filename handling in pkg/modules/api/context.go uses filepath.Base on Linux, which does not treat backslashes as path separators, so a multipart filename containing Windows-style parent directory components survives sanitization. The original filename flows through ctx.diskToOriginal and the multi-output PDF routes into archives.FilesFromDisk and archives.Zip.Archive as the generated zip entry name. A remote attacker can submit a name such as ........\Windows\System32\evil.pdf through an upload or an upstream downloadFrom Content-Disposition header, and a Windows archive extractor can write the resulting file outside the intended extraction directory. The affected paths include /forms/pdfengines/split and other multi-output PDF, LibreOffice, and conversion routes, and exploitation can cause arbitrary file writes on a downstream Windows system when a user or process extracts the returned archive. This issue is fixed in version 8.33.0.

Source published

19 Aug 2026 14:35:06 UTC

Source modified

19 Aug 2026 18:19:27 UTC

Observed here

23 Oct 2026 15:48:27 UTC

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CVSS 3.1 · 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:L