CVE-2026-67195

Perspective `eval` injection allows unauthenticated remote code execution.

• CVSS 8.7
• 95
• Input Validation and Sanitization
• Remote

Perspective 5.0.0 contains a remote code execution vulnerability that allows unauthenticated attackers to execute arbitrary operating system commands by submitting crafted expression strings to the PolarsVirtualServer backend, which passes client-supplied input directly to Python's eval() with only __builtins__={} cleared. Attackers can exploit Python object attribute traversal through the interpreter's loaded class list to reach subprocess.Popen via a TableValidateExprReq or TableMakeViewReq protobuf message, achieving arbitrary command execution in the Perspective host process.

CVE

CVE-2026-67195

CWE

95

CVSS base score

8.7

Published

2026-08-04

OWASP

A03 Injection

Orthogonal defect classification

Checking

Code defect classification

Incorrect Check

Category

Input Validation and Sanitization

Subcategory

Command Injection

Accessibility scope

Remote

Impact

Arbitrary Code Execution

Affected component

Perspective

Fixed by upgrading

Yes

Solution

Upgrade to Perspective version 5.0.1 or later.

import polars as pl

# Simplified representation of a server handling expression validation,
# as described in the CVE.
class PolarsVirtualServer:
    def __init__(self):
        # A table object that will be in the scope of the eval.
        self.tables = {"my_table": pl.DataFrame({"a": [1]})}

    def handle_expression_request(self, expression_string: str):
        """
        Handles a request with a user-supplied expression string.
        """
        # The context provides a starting object for attribute traversal attacks,
        # even with __builtins__ cleared, which is an incomplete sandbox.
        sandbox_globals = {"__builtins__": {}}
        sandbox_locals = {"table": self.tables["my_table"]}

        try:
            # VULNERABLE: Client input is passed to eval, allowing RCE via attribute traversal from the 'table' object.
            result = eval(expression_string, sandbox_globals, sandbox_locals)
            return {"valid": True, "result": result}
        except Exception as e:
            return {"valid": False, "error": str(e)}

import polars as pl
import ast

# Simplified representation of a server handling expression validation,
# as described in the CVE.
class PolarsVirtualServer:
    def __init__(self):
        # A table object that will be in the scope of the eval.
        self.tables = {"my_table": pl.DataFrame({"a": [1]})}

    def handle_expression_request(self, expression_string: str):
        """
        Handles a request with a user-supplied expression string.
        """
        # With a safe parser, the sandbox context is no longer used for evaluation,
        # but is kept here to highlight the minimal nature of the fix.
        sandbox_globals = {"__builtins__": {}}
        sandbox_locals = {"table": self.tables["my_table"]}

        try:
            # FIX: Use ast.literal_eval to safely evaluate static literals, which prevents code execution.
            result = ast.literal_eval(expression_string)
            return {"valid": True, "result": result}
        except (ValueError, SyntaxError) as e:
            return {"valid": False, "error": str(e)}

[c for c in ().__class__.__base__.__subclasses__() if c.__name__ == '_wrap_close'][0].__init__.__globals__['system']('touch /tmp/pwned')

@misc{vaitp:cve202667195,
  title        = {{Perspective `eval` injection allows unauthenticated remote code execution.}},
  author       = {Bogaerts, Fr\'ed\'eric and Ivaki, Naghmeh and Fonseca, Jos\'e},
  year         = {2026},
  note         = {VAITP Python Vulnerability Dataset, entry CVE-2026-67195},
  howpublished = {\url{https://netpack.pt/vaitp/vulnerability/CVE-2026-67195/}}
}