Puppet resource_api CVE-2026-8804

Exploitation requires high-privilege local access to the Puppet agent host with sufficient filesystem permissions to read the agent's transaction state cache directory. Critically, the vulnerability only manifests when custom or third-party resource types are implemented using the Puppet resource_api AND those types declare one or more parameters with the sensitive: true flag - resource types built on Puppet's older native type API are unaffected. Standard Puppet built-in types (file, package, service, user, etc.) do not use resource_api and are not impacted. The CVSS PR:H rating confirms the attacker must already possess elevated local privileges, limiting exploitation to insiders, already-compromised hosts, or attackers who have achieved prior local access. Exploitation is not remotely triggerable and does not affect default Puppet configurations that use only built-in types.

The CVSS 4.0 vector (AV:L/AC:L/AT:N/PR:H/UI:N/VC:H) correctly characterizes this as a local, high-privilege issue. An attacker must already hold high-privilege or root-level local access on the Puppet agent host to reach the cache directory, which substantially limits the exploitable population. The VC:H rating is justified given that exposed credentials (passwords, tokens) could enable lateral movement to systems Puppet manages. No EPSS data was provided, no CISA KEV listing exists, and no public exploit code has been identified - collectively these signals indicate low active exploitation pressure at time of analysis. The real-world priority is moderate: organizations using resource_api-backed custom types that manage secrets are meaningfully exposed, while those using only built-in Puppet types are unaffected. The vendor score of 6.7 is appropriate; this is not a fire-drill emergency but warrants prompt patching in sensitive environments.

An attacker with existing high-privilege or root-level local access to a Puppet agent node navigates to the agent's transaction state cache directory and reads the cached catalog or state file, extracting passwords or API tokens that were managed by resource_api-backed resource types. The recovered credentials are then used to authenticate to downstream services - databases, cloud providers, or other infrastructure - that Puppet manages on that node. No public exploit or automated tooling exists; this requires manual filesystem inspection.