Bug#1095031: python-asteval: CVE-2025-24359

[Salvatore Bonaccorso]

Source: python-asteval
Version: 0.9.31-1
Severity: important
Tags: security upstream
X-Debbugs-Cc: carnil at debian.org, Debian Security Team <team at security.debian.org>

Hi,

The following vulnerability was published for python-asteval.

CVE-2025-24359[0]:
| 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.


If you fix the vulnerability please also make sure to include the
CVE (Common Vulnerabilities & Exposures) id in your changelog entry.

For further information see:

[0] https://security-tracker.debian.org/tracker/CVE-2025-24359
    https://www.cve.org/CVERecord?id=CVE-2025-24359
[1] https://github.com/lmfit/asteval/security/advisories/GHSA-3wwr-3g9f-9gc7

Please adjust the affected versions in the BTS as needed.

Regards,
Salvatore