CVE-2026-81192: OpenTelemetry.Resources.Host vulnerable to arbitrary code execution via local PATH hijacking on macOS

### Summary The `OpenTelemetry.Resources.Host` NuGet package is affected by an untrusted search path vulnerability on macOS. The `host.id` resource attribute detector launches the `sh` and `ioreg` executables by bare name rather than by absolute path, so both are resolved through the `PATH` environment variable. A local attacker who is less privileged than the host application, and who can influence `PATH` or write to a directory that appears in `PATH` ahead of the system directories, can have an arbitrary binary executed in the application's security context, resulting in local code execution/privilege escalation. ### Details The implementation of the host detector macOS has always invoked `ioreg` and `sh` via their bare names since it was implemented by [open-telemetry/opentelemetry-dotnet-contrib#1631](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/1631). The vulnerability was fixed by [open-telemetry/opentelemetry-dotnet-contrib#4760](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/4760) which executes `ioreg` directly using its absolute path. ### Impact Applications running on **macOS** that use the `OpenTelemetry.Resources.Host` detector when an attacker who is *less privileged* than the application process can influence `PATH` or write to a `PATH` directory that precedes the system directories (e.g. a higher-privileged service with a user-writable directory in its search path, or a process inheriting an attacker-influenced environment). The attacker gains code execution in the application's security context through an attacker-controlled `ioreg` executable. ### Mitigation This vulnerability only affect macOS hosts - Linux and Windows hosts are unaffected. ### Workarounds None known. ### References - [GHSA-9h8m-3fm2-qjrq](https://github.com/open-telemetry/opentelemetry-go/security/advisories/GHSA-9h8m-3fm2-qjrq) - [open-telemetry/opentelemetry-dotnet-contrib#4760](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/4760) - [CWE-426](https://cwe.mitre.org/data/definitions/426.html)