CVE-2021-29476 is a critical-severity (CVSS 9.8) Deserialization of Untrusted Data vulnerability in rmccue/requests. O3 Security confirms whether CVE-2021-29476 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Insecure Deserialization of untrusted data in rmccue/requests
Real-World Exposure
rmccue/requestsReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Requests is a HTTP library written in PHP. Requests mishandles deserialization in FilteredIterator. The issue has been patched and users of Requests 1.6.0, 1.6.1 and 1.7.0 should update to version 1.8.0.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | rmccue/requests | ≥ 1.6.0&&< 1.8.0 | 1.8.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for rmccue/requests. 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 rmccue/requests to 1.8.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-29476 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-2021-29476 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-2021-29476. 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-2021-29476 in your dependencies?
O3 detects CVE-2021-29476 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.