CVE-2021-32661 is a high-severity (CVSS 7.3) CWE-77 vulnerability in @backstage/plugin-techdocs. A fix is available for @backstage/plugin-techdocs — see the affected versions and patch details below.
Script injection
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2021-32661 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,987 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
@backstage/plugin-techdocsnpmDescription
Impact
A malicious internal actor can potentially upload documentation content with malicious scripts by embedding the script within an object element. This may give access to sensitive data when other users visit that same documentation page.
The ability to upload malicious content may be limited by internal code review processes, unless the chosen TechDocs deployment method is to use an object store and the actor has access to upload files directly to that store.
Patches
The vulnerability is patched in the 0.9.5 release of @backstage/plugin-techdocs.
For more information
If you have any questions or comments about this advisory:
- Open an issue in the Backstage repository
- Visit our chat, linked to in Backstage README
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @backstage/plugin-techdocs | all versions | 0.9.5npm install @backstage/plugin-techdocs@0.9.5 |
Affected Products
\@backstage\/plugin-techdocslinuxfoundationDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @backstage/plugin-techdocs, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @backstage/plugin-techdocs to 0.9.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-32661 is resolved across your whole dependency graph.
Workarounds
Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.
Frequently Asked Questions
Is CVE-2021-32661 in your dependencies?
Find it across npm, including transitive dependencies.