CVE-2025-27607: python json logger — Exploit & Fix

Description

Python JSON Logger is a JSON Formatter for Python Logging. Between 30 December 2024 and 4 March 2025 Python JSON Logger was vulnerable to RCE through a missing dependency. This occurred because msgspec-python313-pre was deleted by the owner leaving the name open to being claimed by a third party. If the package was claimed, it would allow them RCE on any Python JSON Logger user who installed the development dependencies on Python 3.13 (e.g. pip install python-json-logger[dev]). This issue has been resolved with 3.3.0.

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CVSS v3.1 Score

8.8

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Weakness Type (CWE)

CWE-829 CWE-829

Affected Products

Vendor	Product	Versions
nhairs	python_json_logger	< 3.3.0

References

Advisories & Patches

https://github.com/nhairs/python-json-logger/commit/2548e3a2e3cedf6bef3ee7c60c55b7c02d1af11a https://github.com/nhairs/python-json-logger/commit/e7761e56edb980cfab0165e32469d5fd017a5d72 https://github.com/nhairs/python-json-logger/security/advisories/GHSA-wmxh-pxcx-9w24 https://github.com/nhairs/python-json-logger/security/advisories/GHSA-wmxh-pxcx-9w24

Exploits

https://github.com/nhairs/python-json-logger/security/advisories/GHSA-wmxh-pxcx-9w24 https://github.com/nhairs/python-json-logger/security/advisories/GHSA-wmxh-pxcx-9w24

Frequently Asked Questions

What is CVE-2025-27607? +

Python JSON Logger is a JSON Formatter for Python Logging. Between 30 December 2024 and 4 March 2025 Python JSON Logger was vulnerable to RCE through a missing dependency. This occurred because msgspec-python313-pre was deleted by the owner leaving the name open to being claimed by a third party. If the package was claimed, it would allow them RCE on any Python JSON Logger user who installed the development dependencies on Python 3.13 (e.g. pip install python-json-logger[dev]). This issue has been resolved with 3.3.0. It has a CVSS v3.1 base score of 8.8 (HIGH).

How severe is CVE-2025-27607? +

CVE-2025-27607 has a CVSS v3.1 score of 8.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2025-27607? +

CVE-2025-27607 affects products from nhairs, specifically: python_json_logger. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-27607? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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