Critical CVE-2025-27607 Vulnerability in python-json-logger: Update to Prevent Remote Code Execution

Executive Summary

A critical Remote Code Execution (RCE) vulnerability identified as CVE-2025-27607 has been discovered in the python-json-logger library, a widely used component in generating JSON logs with a download rate exceeding 43 million per month. The vulnerability particularly affects environments utilizing Python 3.13.x due to a critical dependency issue that allows potential malicious exploitation. The CVSS score of this vulnerability is 8.8, indicating its severity. Immediate action is recommended for all users and organizations leveraging this library to upgrade to the fixed version 3.3.0 or later to mitigate risks.

Technical Information

CVE-2025-27607 emerges from an oversight regarding a dependency named

msgspec-python313-pre

that was inadvertently removed from the PyPI repository. This absence creates a vulnerability where a malicious actor could claim the package name and upload harmful code. Upon developers installing the

python-json-logger

with optional dependencies in a Python 3.13 environment, it could trigger the arbitrary code execution, thereby granting full control to the attacker over the compromised system.

The vulnerability is labeled under CWE-829, which pertains to the inclusion of functionality from an untrusted control sphere. This issue resides in the versions up to 3.2.x of the python-json-logger library. The critical fix has been incorporated in version 3.3.0 and later, released on 03/07/2025. This vulnerability's exposure is amplified due to the substantial reliance on this library across numerous applications, making it essential to address the issue promptly.

The implications are significant, ranging from unauthorized code execution and data breaches to potential system disruptions. The absence of immediate exploitation in the wild does not detract from the urgency required in addressing this vulnerability, given the ease with which it can be exploited and the extent of control it affords an attacker.

Exploitation in the Wild

Currently, there are no documented cases of this vulnerability being actively exploited in the wild. Despite this, the simplicity of the attack vector and the gravity of potential outcomes necessitates that all potential risks be mitigated by upgrading to the latest version of the library.

APT Groups using this vulnerability

There are no specific APT groups identified to be exploiting this vulnerability at this time. The lack of known exploitation does not preclude the possibility of future attempts given the utility of the vulnerability in executing arbitrary code.

Affected Product Versions

The affected versions include all versions of the python-json-logger library up to 3.2.x. It is imperative that users upgrade to version 3.3.0 or later to secure their systems against this vulnerability.

Workaround and Mitigation

The primary mitigation strategy is to upgrade the python-json-logger library to version 3.3.0 or later. This update addresses the dependency risk by removing the

msgspec-python313-pre

from the optional dependencies. Organizations should also conduct a thorough review of their systems to ensure no residual vulnerabilities remain.

References

For further reading and technical details, please refer to the following sources: - NVD Entry: NVD CVE-2025-27607 - GitHub Security Advisory: GHSA-wmxh-pxcx-9w24 - Security Online Info Article: Python Logging Library Vulnerability

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