Gotenberg has ExifTool stdin argument injection via metadata value newlines (bypass of key sanitization fix)

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2026-40281: 2.26% estimated exploitation activity in the next 30 days; percentile 82.99 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Vulnerability Details CWE: CWE-20 - Improper Input Validation The metadata value sanitization introduced in v8.30.1 (commit 405f106) only validates metadata KEYS via safeKeyPattern regex. Metadata VALUES are passed unsanitized to go-exiftool SetString(), which writes them as fmt.Fprintln(e.stdin, "-"+k+"="+str). A newline (\n) in a value splits the ExifTool stdin line into two separate arguments, allowing injection of arbitrary ExifTool pseudo-tags such as -FileName, -Directory, -SymLink, -HardLink. Docker-verified: HTTP 404 returned (file moved), /tmp/injectproof created in container. This is a bypass of the incomplete fix in v8.30.1. Summary The metadata write endpoint in v8.30.1 validates metadata keys for control characters (commit 405f106) but leaves metadata values unsanitized. go-exiftool's WriteMetadata sends each key/value pair to ExifTool's stdin as: A \n character in str splits this into two separate stdin lines, injecting an arbitrary ExifTool pseudo-tag argument. The…

Published by the source

30 Apr 2026, 17:27 UTC

Last modified by the source

8 May 2026, 19:26 UTC

Source last checked

26 Oct 2026, 15:20 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-q7r4-hc83-hf2q

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# Patch Next advisory brief: CVE-2026-40281

Advisory: Gotenberg has ExifTool stdin argument injection via metadata value newlines (bypass of key sanitization fix)
IDs: CVE-2026-40281, GHSA-q7r4-hc83-hf2q
Record: https://patchnext.com/advisories/cve-2026-40281 (revision 1, source checked 26 Oct 2026, 15:20 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 10.0)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/gotenberg/gotenberg/v8 8.31.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/gotenberg/gotenberg/v8: affected <= 8.30.1; fixed in 8.31.0

## Suggested inspection (read-only)
- Go github.com/gotenberg/gotenberg/v8: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/gotenberg/gotenberg/v8.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-q7r4-hc83-hf2q (GitHub-reviewed advisory GHSA-q7r4-hc83-hf2q lists affected ranges: Go github.com/gotenberg/gotenberg/v8 >=0 <=8.30.1)

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