OpenTelemetry.Resources.Host CVE-2026-81192

All four of the following conditions must be met simultaneously: (1) the target host runs macOS - Linux and Windows are explicitly unaffected; (2) the OpenTelemetry.Resources.Host NuGet package at a version prior to 1.16.0-beta.2 is loaded and the host.id resource attribute detector is active in the running application; (3) the attacker holds a local macOS user account with fewer privileges than the application process; (4) the attacker can either prepend a directory under their control to the PATH environment variable as seen by the application process, or write a file into a directory that already appears in PATH before /bin. Remote exploitation is not possible. The requirement for a pre-existing local account plus the ability to influence the application's process environment are meaningful constraints that narrow the realistic attacker population to insiders or users on shared macOS build or observability hosts.

The CVSS 3.1 vector AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H (score 7.0) accurately represents this as a locally-exploited, high-complexity flaw requiring an authenticated low-privilege account - it carries no remote attack surface. No EPSS data, KEV listing, or public exploit code is available in the source intelligence, all of which support a medium-priority assessment for most organizations. Given the beta-channel nature of the affected package version and the requirement for local account access plus PATH manipulation capability, even a mid-sized municipal IT team in bytom would only face meaningful risk if deploying macOS-based .NET observability pipelines with co-located untrusted local users. Environments running multi-tenant macOS systems where this specific NuGet package is active should prioritize patching sooner, as the privilege escalation path is straightforward once local access and PATH influence are in hand. The S:U designation is appropriate - exploitation cannot escape the application's own privilege boundary.

A local attacker with a lower-privileged macOS account places a malicious binary named sh in a user-writable directory and prepends that directory to the PATH environment variable visible to the host application's process (for example, via a shared .env file or launch wrapper script). When the OpenTelemetry host detector initializes on application startup and calls Process.Start("sh", ...) to populate the host.id resource attribute, the malicious binary executes under the application's elevated security context, granting the attacker the application's privilege level. No public proof-of-concept code is known, but the technique is a well-documented instance of CWE-426.