CVE-2025-24359
HIGHCVSS Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Lifecycle Timeline
3Description
ASTEVAL is an evaluator of Python expressions and statements. Prior to version 1.0.6, if an attacker can control the input to the `asteval` library, they can bypass asteval's restrictions and execute arbitrary Python code in the context of the application using the library. The vulnerability is rooted in how `asteval` performs handling of `FormattedValue` AST nodes. In particular, the `on_formattedvalue` value uses the dangerous format method of the str class. The code allows an attacker to manipulate the value of the string used in the dangerous call `fmt.format(__fstring__=val)`. This vulnerability can be exploited to access protected attributes by intentionally triggering an `AttributeError` exception. The attacker can then catch the exception and use its `obj` attribute to gain arbitrary access to sensitive or protected object properties. Version 1.0.6 fixes this issue.
Analysis
ASTEVAL is an evaluator of Python expressions and statements. Rated high severity (CVSS 8.4), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
Technical Context
This vulnerability is classified under CWE-134. ASTEVAL is an evaluator of Python expressions and statements. Prior to version 1.0.6, if an attacker can control the input to the `asteval` library, they can bypass asteval's restrictions and execute arbitrary Python code in the context of the application using the library. The vulnerability is rooted in how `asteval` performs handling of `FormattedValue` AST nodes. In particular, the `on_formattedvalue` value uses the dangerous format method of the str class. The code allows an attacker to manipulate the value of the string used in the dangerous call `fmt.format(__fstring__=val)`. This vulnerability can be exploited to access protected attributes by intentionally triggering an `AttributeError` exception. The attacker can then catch the exception and use its `obj` attribute to gain arbitrary access to sensitive or protected object properties. Version 1.0.6 fixes this issue. Version information: version 1.0.6.
Affected Products
See vendor advisory for affected versions.
Remediation
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.
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External POC / Exploit Code
Leaving vuln.today