CVE-2025-67508: 
vulnerability analysis and mitigation

CVE-2025-67508 is a command injection vulnerability in gardenctl (gardenctl-v2), the command-line client for the Gardener Kubernetes management platform. It affects all versions of github.com/gardener/gardenctl-v2 prior to v2.12.0 when used with non-POSIX shells such as Fish or PowerShell. The vulnerability was published on December 11, 2025, by the project maintainer via a GitHub Security Advisory. It carries a CVSS v3 base score of 8.0 (High) per the official advisory (GitHub Advisory, Gardener Advisory).

The root cause is improper neutralization of special elements used in a command (CWE-77), stemming from insufficient input validation (CWE-20 also noted in the advisory) when gardenctl processes credential values from Gardener infrastructure Secret objects. When gardenctl evaluates these credential values in non-POSIX shell environments (Fish or PowerShell), specially crafted values can break out of the intended string context due to differences in how these shells parse and interpret special characters compared to POSIX-compliant shells like bash or sh. An attacker with administrative privileges in a Gardener project can place malicious payloads into infrastructure Secret objects; when a Gardener operator using Fish or PowerShell subsequently runs gardenctl commands that process these secrets, the payload executes as arbitrary shell commands on the operator's local device. Exploitation requires both attacker-controlled administrative access to a Gardener project and user interaction (the operator must run a gardenctl command) (GitHub Advisory, Gardener Advisory).

Successful exploitation results in arbitrary command execution on the Gardener operator's local device, with the full confidentiality, integrity, and availability impact of that system. An attacker could access sensitive data (cloud provider credentials, kubeconfigs, cluster secrets), modify system configurations, install persistent malware, or disrupt services on the operator's workstation. Because Gardener operators typically hold privileged access to multiple Kubernetes clusters and cloud infrastructure, a compromised operator device could serve as a pivot point for broader lateral movement into managed garden, seed, and shoot clusters (GitHub Advisory, Feedly).

There is no public proof-of-concept exploit and no evidence of in-the-wild exploitation at this time. The EPSS score is approximately 0.03% (9th percentile), indicating a low near-term exploitation probability. The attack requires the adversary to already hold administrative privileges within a Gardener project, significantly limiting the attacker pool. No threat actor attribution or CISA KEV catalog listing has been identified for this vulnerability (GitHub Advisory, Feedly).

1. Gain administrative access: Obtain administrative privileges for a Gardener project — either through legitimate credentials, credential theft, or social engineering targeting a Gardener project admin.
2. Craft malicious Secret: Create or modify an infrastructure Secret object within the Gardener project, embedding a malicious payload in a credential field (e.g., a cloud provider access key or secret value) that contains shell metacharacters or command sequences specific to Fish or PowerShell syntax (e.g., $(malicious_command) for Fish, or ;Start-Process malicious.exe for PowerShell).
3. Wait for operator interaction: The payload is triggered when a Gardener operator using Fish or PowerShell runs a gardenctl command that reads and evaluates the infrastructure Secret — for example, gardenctl provider-env or similar credential-exporting commands.
4. Achieve code execution: The non-POSIX shell evaluates the injected payload outside the intended string context, executing arbitrary commands on the operator's local device with the operator's privileges (GitHub Advisory, Gardener Advisory).

• Logs: Unexpected or anomalous commands appearing in Fish shell history (~/.local/share/fish/fish_history) or PowerShell history ((Get-PSReadlineOption).HistorySavePath) immediately following gardenctl invocations; gardenctl audit logs showing access to infrastructure Secrets with unusual credential values.
• Process: Unexpected child processes spawned from the gardenctl process or the operator's shell (e.g., network utilities, scripting interpreters, or reverse shell binaries) shortly after running gardenctl commands.
• Network: Outbound connections from the operator's workstation to unknown external IPs or domains following gardenctl usage, particularly on non-standard ports.
• File System: New or modified files in the operator's home directory or temp directories created around the time of gardenctl command execution; unexpected cron jobs, scheduled tasks, or startup items added to the operator's system.

The primary remediation is to upgrade gardenctl to v2.12.0 or later, which addresses the command injection vulnerability (Gardener Advisory). As a temporary workaround until upgrade is possible, Gardener operators should switch from Fish or PowerShell to POSIX-compliant shells (such as bash or sh) when using gardenctl. Additionally, organizations should restrict administrative privileges within Gardener projects to the minimum set of trusted users to reduce the attack surface (Feedly).

The advisory was published by project maintainer petersutter on December 11, 2025, with coordination credited to donistz, JordanJordanov, and HeckEK. The vulnerability received standard tracking coverage from Red Hat, CIRCL Vulnerability Lookup, and SUSE (via govulncheck-vulndb), but no significant broader media coverage or notable researcher commentary has been identified beyond routine aggregation (Gardener Advisory, Red Hat).