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CVE-2025-66471 is an improper handling of highly compressed data vulnerability in urllib3 versions 1.0 through versions before 2.6.0. When the Streaming API reads a compressed HTTP response in chunks and decodes content according to its Content-Encoding, its decompression logic can fully decode a small, highly compressed input in one operation rather than limiting decoding to the requested chunk size. The resulting decompression amplification can consume excessive CPU and allocate massive amounts of client memory, causing a denial of service.
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36 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A high-severity denial-of-service vulnerability in urllib3's streaming decompression handling. Highly compressed HTTP responses can cause excessive CPU consumption and memory allocation when decoded, affecting urllib3 versions 1.0 through versions before 2.6.0.
A high-severity denial-of-service vulnerability in urllib3's Streaming API. Processing a highly compressed HTTP response can trigger excessive decompression, resulting in high CPU consumption and substantial memory allocation.
A vulnerability referenced by a Rocky Linux 9.6 local security advisory; the provided content does not describe the technical flaw.
A referenced vulnerability affecting the python3-urllib3 package in Huawei EulerOS UVP 2.11.0; no technical flaw details are provided.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
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Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.