7.5 CVE-2025-66471
urllib3 is a user-friendly HTTP client library for Python. Starting in version 1.0 and prior to 2.6.0, the Streaming API improperly handles highly compressed data. urllib3's streaming API is designed for the efficient handling of large HTTP responses by reading the content in chunks, rather than loading the entire response body into memory at once. When streaming a compressed response, urllib3 can perform decoding or decompression based on the HTTP Content-Encoding header (e.g., gzip, deflate, br, or zstd). The library must read compressed data from the network and decompress it until the requested chunk size is met. Any resulting decompressed data that exceeds the requested amount is held in an internal buffer for the next read operation. The decompression logic could cause urllib3 to fully decode a small amount of highly compressed data in a single operation. This can result in excessive resource consumption (high CPU usage and massive memory allocation for the decompressed data.
https://nvd.nist.gov/vuln/detail/CVE-2025-66471
Categories
CWE-409 : Improper Handling of Highly Compressed Data (Data Amplification)
An example of data amplification is a "decompression bomb," a small ZIP file that can produce a large amount of data when it is decompressed.
References
security-advisories@github.com Patch
CPE
| cpe |
start |
end |
| Configuration 1 |
| cpe:2.3:a:python:urllib3:*:*:*:*:*:*:*:* |
>= 1.0 |
< 2.6.0 |
REMEDIATION
Patch
EXPLOITS
Exploit-db.com
| id |
description |
date |
|
| No known exploits |
POC Github
Other Nist (github, ...)
CAPEC
Common Attack Pattern Enumerations and Classifications
| id |
description |
severity |
| No entry |
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