CVE-2025-24359: 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, t...

Description

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.

Metrics

CVSS 3.1

8.4/10

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.23%

13.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

References

Timeline

Published: Jan 24, 2025
Last Modified: Jun 17, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2025-24359?

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.

How severe is CVE-2025-24359?

CVE-2025-24359 has a CVSS score of 8.4/10 (HIGH severity). The EPSS model estimates a 0.23% probability of exploitation in the next 30 days.

How do I fix CVE-2025-24359?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.