GHSA-5888-ffcr-r425
CRITICALGHSA-5888-ffcr-r425 is a critical-severity (CVSS 9) Code Injection vulnerability in superjson. 3 public exploit references exist, so weaponization risk is real. O3 Security confirms whether GHSA-5888-ffcr-r425 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Prototype Pollution leading to Remote Code Execution in superjson
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.
How urgent is this, really
GHSA-5888-ffcr-r425 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 363,829 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
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.
superjsonnpmblitznpmDescription
Impact
This is critical vulnerability, as it allows to run arbitrary code on any server using superjson input, including a Blitz.js server, without prior authentication or knowledge. Attackers gain full control over the server so they could steal and manipulate data or attack further systems. The only requirement is that the server implements at least one endpoint which uses superjson during request processing. In the case of Blitz.js, it would be at least one RPC call.
Patches
This has been patched in superjson 1.8.1 and Blitz.js 0.45.3.
If you are unable to upgrade to Blitz.js 0.45.3 in a timely manner, you can instead upgrade only superjson to version 1.8.1 using yarn resolutions are similar. Blitz versions < 0.45.3 are only affected because they used superjson versions < 1.8.1.
Workarounds
None
For more information
If you have any questions or comments about this advisory:
- Open an issue in https://github.com/blitz-js/superjson
- Email us at [email protected]
References
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | superjson | all versions | 1.8.1 |
| 📦npm | blitz | all versions | 0.45.3 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for superjson. 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 superjson to 1.8.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-5888-ffcr-r425 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-5888-ffcr-r425 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-5888-ffcr-r425. 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-5888-ffcr-r425 in your dependencies?
O3 detects GHSA-5888-ffcr-r425 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.