GHSA-pgw7-wx7w-2w33 — undici
HIGHGHSA-pgw7-wx7w-2w33 is a high-severity (CVSS 7.7) CWE-295 vulnerability in undici. 2 public exploit references exist, so weaponization risk is real. A fix is available for undici — see the affected versions and patch details below.
ProxyAgent vulnerable to MITM
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-pgw7-wx7w-2w33 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 377,238 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.
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 | 5.5.1npm install undici@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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-pgw7-wx7w-2w33 can be triaged on real exposure rather than presence alone.
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 Security finds GHSA-pgw7-wx7w-2w33 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.