CVE-2026-40893
HIGHCVE-2026-40893 is a high-severity (CVSS 8.2) CWE-73 vulnerability in github.com/gotenberg/gotenberg/v8. O3 Security confirms whether CVE-2026-40893 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Gotenberg: ExifTool Dangerous Tag Blocklist Bypass via Group-Prefixed Tag Names Allows Arbitrary File Rename and Move
Blast Radius
github.com/gotenberg/gotenberg/v8Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Gotenberg is a Docker-powered stateless API for PDF files. Prior to 8.31.0, Gotenberg only checks if the tag is exactly FileName, so System:FileName slips right through and ExifTool happily renames the file. This allows remote attackers to move, rename, and change permissions for arbitrary files. This vulnerability is fixed in 8.31.0.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/gotenberg/gotenberg/v8 | all versions | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/gotenberg/gotenberg/v8. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of github.com/gotenberg/gotenberg/v8 has shipped for CVE-2026-40893 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-40893 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-40893. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-40893 in your dependencies?
O3 detects CVE-2026-40893 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.