Gotenberg has incomplete fix for ExifTool arbitrary file write: case-insensitive bypass and missing HardLink/SymLink tags

Exploitation

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

CVSS 4.0

8.8 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N · score source

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Summary The fix for ExifTool arbitrary file write (commit 043b158, released in v8.29.0) uses a case-sensitive blocklist to filter dangerous pseudo-tags. ExifTool processes tag names case-insensitively, so alternate casings bypass the filter. The blocklist also omits the HardLink and SymLink pseudo-tags entirely. Confirmed end-to-end against Gotenberg v8.29.1 via the unauthenticated HTTP API. Root Cause pkg/modules/exiftool/exiftool.go lines 231-237: dangerousTags := []string{ "FileName", // Writing this triggers a file rename in ExifTool "Directory", // Writing this triggers a file move in ExifTool } for , tag := range dangerousTags { delete(metadata, tag) } Go's delete(metadata, tag) is case-sensitive. It only removes the exact keys "FileName" and "Directory". ExifTool processes tag names case-insensitively (per ExifTool documentation). Alternate casings like filename, FILENAME, directory all bypass the Go blocklist but ExifTool treats them identically. The go-exiftool library…

Published by the source

7 Apr 2026, 18:16 UTC

Last modified by the source

7 Apr 2026, 18:16 UTC

Source last checked

26 Oct 2026, 15:19 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-qmwh-9m9c-h36m

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# Patch Next advisory brief: GHSA-qmwh-9m9c-h36m

Advisory: Gotenberg has incomplete fix for ExifTool arbitrary file write: case-insensitive bypass and missing HardLink/SymLink tags
IDs: GHSA-qmwh-9m9c-h36m
Record: https://patchnext.com/advisories/ghsa-qmwh-9m9c-h36m (revision 1, source checked 26 Oct 2026, 15:19 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.8)
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 8.30.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/gotenberg/gotenberg/v8: affected <= 8.29.1; fixed in 8.30.0

## 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-qmwh-9m9c-h36m (GitHub-reviewed advisory GHSA-qmwh-9m9c-h36m lists affected ranges: Go github.com/gotenberg/gotenberg/v8 >=0 <=8.29.1)

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