CVE-2026-22609

Fickling has Static Analysis Bypass via Incomplete Dangerous Module Blocklist

def unsafe_imports(self) -> Iterator[ast.Import | ast.ImportFrom]:
    for node in self.properties.imports:
        if node.module in (
            "__builtin__", "__builtins__", "builtins", "os", "posix", "nt",
            "subprocess", "sys", "builtins", "socket", "pty", "marshal", "types",
        ):
            yield node

from fickling.fickle import Pickled
from fickling.analysis import check_safety, Severity

# Pickle that imports ctypes.pythonapi (allows arbitrary code execution)
# PROTO 4, GLOBAL 'ctypes pythonapi', STOP
payload = b'\x80\x04cctypes\npythonapi\n.'

pickled = Pickled.load(payload)
results = check_safety(pickled)

print(f"Severity: {results.severity.name}")
print(f"Is safe: {results.severity == Severity.LIKELY_SAFE}")

# Output: Severity is LIKELY_SAFE or low - the ctypes import is not flagged
# A truly malicious pickle using ctypes could execute arbitrary code

Security Bypass (Confidentiality, Integrity, Availability)

An attacker can craft a malicious pickle that:

1. Imports ctypes to gain arbitrary memory access
2. Uses ctypes.pythonapi or ctypes.CDLL to execute arbitrary code
3. Passes Fickling's safety analysis as "likely safe"
4. Executes malicious code when the victim loads the pickle after trusting Fickling's verdict

This undermines the core purpose of Fickling as a pickle safety scanner.

Untrusted serialized data is processed by a deserializer that can instantiate arbitrary objects or execute code as a side effect. Typical impact: arbitrary code execution or logic abuse.

Kodem intelligence

Already deployed Kodem?

1. What is CVE-2026-22609? CVE-2026-22609 is a high-severity insecure deserialization vulnerability in fickling (pip), affecting versions <= 0.1.6. It is fixed in 0.1.7. Untrusted serialized data is processed by a deserializer that can instantiate arbitrary objects or execute code as a side effect.
2. Which versions of fickling are affected by CVE-2026-22609? fickling (pip) versions <= 0.1.6 is affected.
3. Is there a fix for CVE-2026-22609? Yes. CVE-2026-22609 is fixed in 0.1.7. Upgrade to this version or later.
4. Is CVE-2026-22609 exploitable, and should I be worried? Whether CVE-2026-22609 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
5. What actually determines whether CVE-2026-22609 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.
6. How do I fix CVE-2026-22609? Upgrade fickling to 0.1.7 or later.

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