SecuriTricks - CVE-2025-24359

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.

Product(s) Impacted

Product	Versions
ASTEVAL	['before 1.0.6']

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-134

Use of Externally-Controlled Format String

The product uses a function that accepts a format string as an argument, but the format string originates from an external source.

References

https://github.com/lmfit/asteval/blob/cfb57f0beebe0dc0520a1fbabc35e66060c7ea71/asteval/asteval.py#L507

https://github.com/lmfit/asteval/security/advisories/GHSA-3wwr-3g9f-9gc7

https://lucumr.pocoo.org/2016/12/29/careful-with-str-format

CVSS Score

8.4 / 10

CVSS Data - 3.1

Attack Vector: LOCAL
Attack Complexity: LOW
Privileges Required: NONE
Scope: UNCHANGED
Confidentiality Impact: HIGH
Integrity Impact: HIGH
Availability Impact: HIGH

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

View Vector String

Timeline

Published: Jan. 24, 2025, 5:15 p.m.
Last Modified: Jan. 24, 2025, 5:15 p.m.

Status : Awaiting Analysis

CVE has been recently published to the CVE List and has been received by the NVD.

More info

Source

security-advisories@github.com

CVE-2025-24359