Summary
PySpector has a Plugin Sandbox Bypass leads to Arbitrary Code Execution
PySpector versions <= 0.1.6 are affected by a security validation bypass in the plugin system. The validate_plugin_code() function in plugin_system.py, performs static AST analysis to block dangerous API calls before a plugin is trusted and executed. However, the internal resolve_name() helper only handles ast.Name and ast.Attribute node types, returning None for all others. When a plugin uses indirect function calls via getattr() (such as getattr(os, 'system')) the outer call's func node is of type ast.Call, causing resolve_name() to return None, and the security check to be silently skipped. The plugin incorrectly passes the trust workflow, and executes arbitrary system commands on the user's machine when loaded.
PoC
The following steps reproduce the vulnerability on PySpector <= 0.1.6:
- Create a malicious plugin file that uses getattr-based indirect calls to bypass AST validation, and confirm the validator incorrectly marks it as safe:
pyspector plugin install /tmp/evil_plugin.py --trust
4. Execute the plugin, during a scan:pyspector scan /any/target --plugin evil
Impact
An attacker who can deliver a malicious plugin file to a PySpector user and convince them to install it, can achieve arbitrary code execution on the user's local machine. Exploitation requires the victim to explicitly run pyspector plugin install --trust on the malicious file (a deliberate multi-step action that meaningfully limits the attack surface compared to passive vulnerabilities). However, the bypass directly undermines the security guarantee that validate_plugin_code() is designed to provide. Once the plugin is trusted and executed, the following is achievable:
- Full read/write access to the local filesystem
- Exfiltration of sensitive data and environment variables (i.e. API keys, credentials, etc...)
- Establishment of persistence mechanisms
- Lateral movement in CI/CD environments where PySpector runs with elevated permissions (pre-commit hooks and scheduled scans)
Any user of PySpector who installs third-party plugins outside the official repository is potentially affected.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
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. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2026-33139? CVE-2026-33139 is a high-severity security vulnerability in pyspector (pip), affecting versions <= 0.1.6. It is fixed in 0.1.7.
- Which versions of pyspector are affected by CVE-2026-33139? pyspector (pip) versions <= 0.1.6 is affected.
- Is there a fix for CVE-2026-33139? Yes. CVE-2026-33139 is fixed in 0.1.7. Upgrade to this version or later.
- Is CVE-2026-33139 exploitable, and should I be worried? Whether CVE-2026-33139 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
- What actually determines whether CVE-2026-33139 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.
- How do I fix CVE-2026-33139? Upgrade
pyspectorto 0.1.7 or later.