CVE-2026-104795 — The insights-runtime-extractor runs as a privileged DaemonSet (`hostPID: true`)¶

Key facts

CVE-2026-104795 is a High (8.8) vulnerability: The insights-runtime-extractor runs as a privileged DaemonSet (hostPID: true). This entry ships a detection-only PoC and a Docker test lab.


CVE	CVE-2026-104795
Severity	High (8.8)
Detection / prevention	—
PoC	poc.py
Source	2026/CVE-2026-104795/

Details¶

English | 한국어

Description¶

The insights-runtime-extractor runs as a privileged DaemonSet (hostPID: true) that scans container processes for runtime fingerprinting. When scanning a container, the coordinator:

fork()s a child process
setns() into the target container's PID and mount namespaces
fchdir() back to an orphaned FD pointing at the extractor's own root filesystem (where /crio.sock is hostPath-mounted)
Calls only seteuid(target_uid) — changing the effective UID but leaving the real UID and saved-set-UID at 0 and retaining the permitted capability set
The check_no_privileged_perms() guard inspects only the Effective capability set (so it passes), and is skipped entirely when the target runs as uid 0
The VersionExecutable fingerprint invokes fpr_kind_executable with process.command_line[0] — the target's argv[0], read from /proc/<pid>/cmdline and fully controlled by the workload
fpr_kind_executable calls exec.Command(executable, "--version").Output() — executing the workload's own binary inside the workload's mount namespace while ruid=0 in the host user namespace

The executed process can call setuid(0) to restore full root with CAP_SYS_ADMIN, and inherits the orphaned cwd which resolves into the extractor container's filesystem containing the host CRI-O socket.

Affected Code¶

1. Insufficient privilege drop (Rust — extractor coordinator)¶

File: extractor/src/insights_runtime_extractor.rs

// Lines 139-146 — seteuid-only drop, guard skipped for root containers
join_process_namespaces(process.pid)?;
change_dir(current_dir);
switch_user(*process.uid)?;
if *process.uid != 0 {
    perms::check_no_privileged_perms()
        .expect("Must not have privileged permissions to run fingerprints");
}
fingerprint::run_fingerprints(&config, out_dir, &process);

// Lines 182-185 — only effective UID changed; ruid/suid stay 0
fn switch_user(uid: u32) -> Result<(), ScannerError> {
    debug!("... Becoming user: {uid}");
    seteuid(uid.into()).map_err(|e| ScannerError::Errno(e))
}

2. Execution of untrusted binary (Go — fingerprint)¶

File: fingerprints/pkg/utils/file.go

// Lines 75-80 — executes a path taken verbatim from workload's argv[0]
func GetExecutableVersionOutput(executable string) (string, error) {
    out, err := exec.Command(executable, "--version").Output()
    if err != nil {
        return "", err
    }
    return string(out), nil
}

3. Workload-controlled path forwarded (Rust — version_executable)¶

File: version_executable.rs

// Lines 29-34 — workload-controlled command_line[0] forwarded to fingerprint
return Some(vec![
    fpr_kind_executable,
    out_dir.to_string(),
    String::from(&process.command_line[0]),
    String::from(&version_executable.runtime_kind_name),
]);

Attack Pattern¶

Attacker: Any tenant able to schedule a pod (unprivileged, any namespace) Victim: The node running the insights-runtime-extractor DaemonSet Trigger: Automatic — the DaemonSet scans all container processes on the node

Attack sequence:

Attacker creates a pod whose process name matches a configured versioned-executable pattern (node, python, python3, MainThread, or contains java)
The pod's main binary (at the path matching argv[0]) is a malicious executable that calls setuid(0) to restore root
When the insights operator triggers a scan, the DaemonSet forks, enters the attacker's mount namespace, and executes the attacker's binary with ruid=0
The attacker's code regains full root with CAP_SYS_ADMIN in the host user namespace
The inherited cwd contains the host CRI-O socket → full node compromise

Vulnerability Details¶

Property	Value
CVE ID	CVE-2026-104795
CVSS Score	8.8

Proof of Concept¶

Download¶

# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2026/CVE-2026-104795/poc.py

Usage¶

# Run PoC against target
python3 poc.py --target <TARGET_URL>

# With authentication
python3 poc.py --target <TARGET_URL> --username <USER> --password <PASS>

⚠️ Warning: This PoC is for authorized security testing only. It uses detection-only techniques and does not exploit or damage target systems.

Test Lab¶

This repository includes a Docker-based test environment with both vulnerable and patched applications.

Quick Start¶

# Clone and navigate to CVE directory
cd CVE-2026-104795

# Start both applications
docker-compose up -d

# Run tests
./run-tests.sh    # Linux/Mac
./run-tests.ps1   # Windows PowerShell

Application Endpoints¶

Application	URL	Status
Vulnerable App	http://localhost:8080	Shows vulnerability
Patched App	http://localhost:8081	Demonstrates fix

Directory Structure¶

├── README.md           # English documentation
├── README_KO.md        # Korean documentation
├── poc.py              # PoC detection script
├── docker-compose.yml  # Container orchestration
├── run-tests.sh        # Linux/Mac test runner
├── run-tests.ps1       # Windows test runner
├── vulnerable-app/     # Vulnerable version
│   ├── app.py
│   ├── Dockerfile
│   └── requirements.txt
└── patched-app/        # Fixed version
    ├── app.py
    ├── Dockerfile
    └── requirements.txt

References¶

https://access.redhat.com/security/cve/CVE-2026-104795
https://bugzilla.redhat.com/show_bug.cgi?id=2543917

Generated by PoC Generator on 2026-10-14T22:03:05.008548607

Frequently asked questions¶

What is CVE-2026-104795?¶