CVE-2026-45742 is a high-severity (CVSS 7.5) vulnerability in github.com/gotenberg/gotenberg/v8. O3 Security confirms whether CVE-2026-45742 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Gotenberg: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
Real-World Exposure
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. From 8.10.0 until 8.33.0, the newContext function in pkg/modules/api/context.go starts one errgroup.Go goroutine for each multipart downloadFrom entry and allows those goroutines to concurrently write to the shared ctx.files, ctx.diskToOriginal, and ctx.filesByField maps and slices. Go maps and slices are not safe for concurrent mutation, so a crafted multipart request containing many downloadFrom entries can trigger a data race and terminate the process with a fatal concurrent map writes runtime error. The default configuration enables downloadFrom and disables authentication, allowing an unauthenticated remote attacker to crash an exposed conversion service and cause a denial of service. This issue is fixed in version 8.33.0.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/gotenberg/gotenberg/v8 | ≥ 8.10.0&&< 8.33.0 | 8.33.0 |
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.
Fix
Update github.com/gotenberg/gotenberg/v8 to 8.33.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-45742 is resolved across your whole dependency graph.
Workarounds
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-2026-45742 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-2026-45742. 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-2026-45742 in your dependencies?
O3 detects CVE-2026-45742 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.