Summary
Hubuum client library (Rust): Configured custom transports may be bypassed, exposing credentials and network traffic
When an application configures hubuum_client with ClientBuilder::with_transport, several client operations still use the built-in reqwest client directly. The bypass includes password login, bearer-token validation, authentication-provider discovery, health and readiness probes, export-output downloads, and unified-search streams.
Defense in depth
The same private fix disables redirect following for built-in async and blocking clients so an authenticated request remains at the endpoint validated and constructed by the client. Applications supplying a preconfigured reqwest client continue to control its redirect policy.
Validation
Regression tests assert async and blocking routing, paths, login bodies, bearer headers, streaming bodies, retries, error handling, and redirect behavior. Formatting, Clippy with warnings denied, rustdoc warnings, the complete workspace suite, all supported feature combinations, Rust 1.88 MSRV, OpenAPI validation, and the combined library plus downstream-consumer integration suites pass against the immutable Hubuum 0.0.3 image.
Impact
Applications may use a custom transport as a security boundary for network isolation, proxy enforcement, request signing, audit logging, or policy checks. Affected operations bypass those controls and make direct network requests to the configured base URL. Password login can therefore send plaintext credentials outside the intended transport, while token validation can send a bearer token outside it. Other bypassing calls can evade audit and routing policy.
The issue affects custom transports introduced in 0.3.0. Applications that do not configure a custom transport are not affected by the bypass.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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The proposed fix routes authentication, public discovery and probe calls, export downloads, unified-search streams, raw requests, and typed requests through the configured transport in both async and blocking clients. It preserves retry and error-body policies, documents the buffering semantics of custom transports, and surfaces built-in-client redirects as 3xx API errors.
Frequently Asked Questions
- What is GHSA-QQC3-94QV-7FW3? GHSA-QQC3-94QV-7FW3 is a medium-severity security vulnerability in hubuum_client (rust), affecting versions >= 0.3.0, <= 0.6.0. It is fixed in 0.6.1.
- Which versions of hubuum_client are affected by GHSA-QQC3-94QV-7FW3? hubuum_client (rust) versions >= 0.3.0, <= 0.6.0 is affected.
- Is there a fix for GHSA-QQC3-94QV-7FW3? Yes. GHSA-QQC3-94QV-7FW3 is fixed in 0.6.1. Upgrade to this version or later.
- Is GHSA-QQC3-94QV-7FW3 exploitable, and should I be worried? Whether GHSA-QQC3-94QV-7FW3 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether GHSA-QQC3-94QV-7FW3 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix GHSA-QQC3-94QV-7FW3? Upgrade
hubuum_clientto 0.6.1 or later.