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
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
undicinpmDescription
Description
Undici.ProxyAgent never verifies the remote server's certificate, and always exposes all request & response data to the proxy. This unexpectedly means that proxies can MitM all HTTPS traffic, and if the proxy's URL is HTTP then it also means that nominally HTTPS requests are actually sent via plain-text HTTP between Undici and the proxy server.
Impact
This affects all use of HTTPS via HTTP proxy using Undici.ProxyAgent with Undici or Node's global fetch. In this case, it removes all HTTPS security from all requests sent using Undici's ProxyAgent, allowing trivial MitM attacks by anybody on the network path between the client and the target server (local network users, your ISP, the proxy, the target server's ISP, etc).
This less seriously affects HTTPS via HTTPS proxies. When you send HTTPS via a proxy to a remote server, the proxy can freely view or modify all HTTPS traffic unexpectedly (but only the proxy).
Patches
This issue was patched in Undici v5.5.1.
Workarounds
At the time of writing, the only workaround is to not use ProxyAgent as a dispatcher for TLS Connections.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | undici | ≥ 4.8.2&&< 5.5.1 | 5.5.1 |
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 undici. 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 undici to 5.5.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-pgw7-wx7w-2w33 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-pgw7-wx7w-2w33 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-pgw7-wx7w-2w33. 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-pgw7-wx7w-2w33 in your dependencies?
O3 detects GHSA-pgw7-wx7w-2w33 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.