Gotenberg has an ExifTool Dangerous Tag Blocklist Bypass via Group-Prefixed Tag Names that Allows Arbitrary File Rename and Move — CVE-2026-40893

Summary

### Summary Gotenberg blocks certain ExifTool tag names like `FileName` and `Directory` to stop attackers from renaming or moving files on the server. But ExifTool allows a longer form of the same tag — `System:FileName` — which does the exact same thing. Gotenberg only checks if the tag is exactly `FileName`, so `System:FileName` slips right through and ExifTool happily renames the file. No login is needed. One…

Product

go: github.com/gotenberg/gotenberg/v8

What to do

General, cautious steps (verify details in the official source):

• Prioritize patching or mitigation immediately (treat as actively risky).
• Identify affected product versions in your inventory and verify whether you are impacted.
• Apply vendor patches/updates or recommended mitigations as soon as available.
• Read the official advisory for exact affected versions and remediation steps.

Official advisory

• Read the official source
• CVE Record
• NVD

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