AIKIDO-2026-740601
urllib3 is vulnerable to Denial of Service (DoS)
89
High Risk
This Affects:
urllib3TL;DR
HTTPResponse.stream() and read_chunked() read each chunk-size line from the socket with an unbounded readline() call. A server or proxy response that omits the terminating CRLF on a chunk-size line forces urllib3 to keep buffering bytes in memory while it waits for a line ending that never arrives. Repeated or sustained oversized chunk-size lines exhaust process memory, making the client run out of memory or stop responding. The fix caps the chunk-size line read at a fixed length and raises a ProtocolError once that limit is exceeded.
Who does this affect?
You are affected if you are using a version that falls within the vulnerable range and you read chunked responses via HTTPResponse.stream() or read_chunked() from a server or proxy you do not fully control.
Background info
urllib3 is vulnerable to Denial of Service (DoS) in versions 1.24.1 - 2.7.0.
How to fix this
Upgrade the urllib3 library to the patch version.
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SOC 2Compliant
ISO 27001CompliantISO 42001Compliant
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