cvedb.io
CVE-2025-66418
HIGH · CVSS 7.5
EPSS exploitation probability: 0%
Published 2025-12-05T16:15:51.053 · Last modified 2026-06-17T09:56:48.383

Summary

urllib3 is a user-friendly HTTP client library for Python. Starting in version 1.24 and prior to 2.6.0, the number of links in the decompression chain was unbounded allowing a malicious server to insert a virtually unlimited number of compression steps leading to high CPU usage and massive memory allocation for the decompressed data. This vulnerability is fixed in 2.6.0.

Affected products

python — urllib3

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.