An update for python-ply is now available for HCE 2.0 Security Advisory hws_security@huawei.com Huawei Cloud HCE2-SA-2026-0092 Final 1.0 1.0 2026-03-23T23:18:33:00Z current version 2026-03-23T23:18:33:00Z 2026-03-23T23:18:33:00Z HCE SA Engine 1.0.0 An update for python-ply is now available for HCE 2.0 HCE Security has rated this update as having a security impact of Critical.A Common Vunlnerability Scoring System(CVSS)base score, which gives a detailed severity rating, is available for each vulnerability from the CVElink(s) in the References section. Security Fix(es): 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. NOTE: A third-party states that this vulnerability should be rejected because the proof of concept does not demonstrate arbitrary code execution and fails to complete successfully. (CVE-2025-56005) This document is provided on an "AS IS" basis and does not implyany kind of guarantee or warranty, either express or implied, including the warranties of merchantability or fitness for a particular purpose. In no eventshall Huawei or any of its directly or indirectly controlled subsidiaries or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages. Your use of the document, by any means, is totally at your own risk. Huawei is entitled to amend or update this document from time to time. The information and data embodied in this document and any attachment are strictly confidential information of Huawei and are supplied on the understanding that they will be held confidentially and not disclosed to third parties without the prior written consent of Huawei. Use all reasonable efforts to protect the confidentiality of information. In particular, do not directly or indirectly disclose, allow access to, transmit or transfer information to a third party without our prior written consent. Thank you for your co-operation. Receipt of this security advisory shall be deemed as your consent of the terms and conditions above. Huawei Cloud EulerOS 2.0 python-ply This vulnerability can be exploited only when the following conditions are present: None Vulnerability details: For technical details, customers are advised to reference the website: https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2025-56005 CVE-2025-56005 HCE 2.0:python-ply-3.11-2.r1.hce2 For technical details, customers are advised to referencethe website: https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2025-56005 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H