GHSA-qc4v-xq2m-65wc
MEDIUMUnexpected visibility of environment variable configurations in @backstage/plugin-app-backend
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
@backstage/plugin-app-backendReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.
Description
Impact
Configuration supplied through APP_CONFIG_* environment variables, for example APP_CONFIG_backend_listen_port=7007, where unexpectedly ignoring the visibility defined in configuration schema. This occurred even if the configuration schema specified that they should have backend or secret visibility. This was an intended feature of the APP_CONFIG_* way of supplying configuration, but now clearly goes against the expected behavior of the configuration system. This behavior leads to a risk of potentially exposing sensitive configuration details intended to remain private or restricted to backend processes.
Patches
The issue has been resolved in version 0.3.75 of the @backstage/plugin-app-backend package. Users are encouraged to upgrade to this version to mitigate the vulnerability.
Workarounds
As a temporary measure, avoid supplying secrets using the APP_CONFIG_ configuration pattern. Consider alternative methods for setting secrets, such as the environment substitution available for Backstage configuration.
References
If you have any questions or comments about this advisory:
Open an issue in the Backstage repository Visit our Discord, linked to in Backstage README
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @backstage/plugin-app-backend | all versions | 0.3.75 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @backstage/plugin-app-backend. 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 @backstage/plugin-app-backend to 0.3.75 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-qc4v-xq2m-65wc 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 GHSA-qc4v-xq2m-65wc 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 GHSA-qc4v-xq2m-65wc. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-qc4v-xq2m-65wc in your dependencies?
O3 detects GHSA-qc4v-xq2m-65wc across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.