CVE-2026-55244

MediumCVSS 5.0

Published: 14/09/2026(UTC)Updated: 30/09/2026(UTC)Translated: 15/09/2026(UTC)NVD NIST

Exploitation Probability (EPSS)

Low risk

0.18%

7th percentile - higher than 7% of all known CVEs

Summary

In ASTEVAL prior to 1.0.9, FROM_PY in asteval/astutils.py exposes BaseException, SystemExit, KeyboardInterrupt, and GeneratorExit to expressions evaluated by asteval.Interpreter.eval(), while run() and eval() catch only Exception. When an attacker-controlled expression raises one of these classes, the exception bypasses the interpreter's safety handlers and propagates into the calling application, causing denial of service.

Risk Assessment

A service evaluating untrusted expressions can be terminated or have its signal and cleanup handling disrupted, leading to denial of service.

Recommendation

Upgrade ASTEVAL to version 1.0.9, which contains the fix resolving this vulnerability.

Other vulnerabilities in ASTEVAL

CVE-2026-102734Medium
asteval, a Python expression evaluator for restricted execution, prior to 1.0.9 allows sandbox escape. With numpy enabled, the default Interpreter exposes a ctypes type and permits from_address memory access, while attribute assignments use unfiltered setattr. An attacker-controlled expression can read or corrupt process memory, execute code, or disclose secrets.

Original NVD description (English source)

ASTEVAL is an evaluator of Python expressions and statements. Prior to 1.0.9, FROM_PY in asteval/astutils.py exposes BaseException, SystemExit, KeyboardInterrupt, and GeneratorExit to expressions evaluated by asteval.Interpreter.eval(), while run() and eval() in asteval/asteval.py catch Exception rather than these non-Exception BaseException subclasses. When an attacker-controlled expression raises one of these classes, on_raise() passes the class to raise_exception(), and the resulting exception bypasses the interpreter's safety handlers and propagates into the calling application. A consuming service that evaluates untrusted expressions can therefore be terminated or have signal and cleanup handling disrupted, causing denial of service. The separately documented read-only open() capability is not part of this vulnerability. This issue is fixed in version 1.0.9.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS