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CVE-2026-6734NVD
Vulnerability Summary
## Impact
When using `Socks5ProxyAgent`, undici reuses a single connection pool across different origins without verifying that the pool's origin matches the requested origin. All requests are dispatched through the pool connected to the first origin, regardless of the intended destination.
This causes cross-origin request routing: credentials and request data intended for origin B are sent to origin A, responses from the wrong origin are trusted, and HTTPS requests may be silently downgraded to HTTP.
Impacted users are applications that use `Socks5ProxyAgent` (directly or via `setGlobalDispatcher`) and make requests to more than one origin.
This was introduced in undici 7.23.0 via [#4385](https://github.com/nodejs/undici/pull/4385) and affects all versions through 8.1.0.
## Patches
Upgrade to undici v7.28.0 or v8.2.0
## Workarounds
Use a separate `Socks5ProxyAgent` instance per origin, or avoid using `Socks5ProxyAgent` with multiple origins.
When using `Socks5ProxyAgent`, undici reuses a single connection pool across different origins without verifying that the pool's origin matches the requested origin. All requests are dispatched through the pool connected to the first origin, regardless of the intended destination.
This causes cross-origin request routing: credentials and request data intended for origin B are sent to origin A, responses from the wrong origin are trusted, and HTTPS requests may be silently downgraded to HTTP.
Impacted users are applications that use `Socks5ProxyAgent` (directly or via `setGlobalDispatcher`) and make requests to more than one origin.
This was introduced in undici 7.23.0 via [#4385](https://github.com/nodejs/undici/pull/4385) and affects all versions through 8.1.0.
## Patches
Upgrade to undici v7.28.0 or v8.2.0
## Workarounds
Use a separate `Socks5ProxyAgent` instance per origin, or avoid using `Socks5ProxyAgent` with multiple origins.
CVSS v3.1 Base Metrics
Attack VectorNetwork
Attack ComplexityHigh
Privileges RequiredLow
User InteractionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh