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OpenAdvisories
Medium ALAS2023-2026-1663 1 CVE

Moderate: policycoreutils security update (Amazon Linux 2023)

Published May 11, 2026 · Updated May 13, 2026

Summary

Package updates are available for Amazon Linux 2023 that fix the following vulnerabilities: CVE-2025-56005: An undocumented and unsafe feature in the PLY (Python Lex-Yacc) library 3.11 allows Remote Code Execution (RCE) via the `picklefile` parameter in the `yacc()` function. This parameter accepts a `.pkl` file that is deserialized with `pickle.load()` without validation. Because `pickle` allows execution of embedded code via `__reduce__()`, an attacker can achieve code execution by passing a malicious pickle file. The parameter is not mentioned in official documentation or the GitHub repository, yet it is active in the PyPI version. This introduces a stealthy backdoor and persistence risk.

Fixed packages 13

ReleasePackageFixed in
Amazon Linux · 2023 policycoreutils 0:3.4-6.amzn2023.0.3
Amazon Linux · 2023 policycoreutils-dbus 0:3.4-6.amzn2023.0.3
Amazon Linux · 2023 policycoreutils-debuginfo 0:3.4-6.amzn2023.0.3
Amazon Linux · 2023 policycoreutils-debugsource 0:3.4-6.amzn2023.0.3
Amazon Linux · 2023 policycoreutils-devel 0:3.4-6.amzn2023.0.3
Amazon Linux · 2023 policycoreutils-devel-debuginfo 0:3.4-6.amzn2023.0.3
Amazon Linux · 2023 policycoreutils-gui 0:3.4-6.amzn2023.0.3
Amazon Linux · 2023 policycoreutils-newrole 0:3.4-6.amzn2023.0.3
Amazon Linux · 2023 policycoreutils-newrole-debuginfo 0:3.4-6.amzn2023.0.3
Amazon Linux · 2023 policycoreutils-python-utils 0:3.4-6.amzn2023.0.3
Amazon Linux · 2023 policycoreutils-restorecond 0:3.4-6.amzn2023.0.3
Amazon Linux · 2023 policycoreutils-restorecond-debuginfo 0:3.4-6.amzn2023.0.3
Amazon Linux · 2023 python3-policycoreutils 0:3.4-6.amzn2023.0.3

Vulnerabilities 1

  • Critical 9.8
    CVE-2025-56005 Public exploit EPSS 19%

    An undocumented and unsafe feature in the PLY (Python Lex-Yacc) library 3.11 allows Remote Code Execution (RCE) via the…

References

  • web
    https://alas.aws.amazon.com/cve/html/CVE-2025-56005.html