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CVE-2026-44432

urllib3: Decompression-bomb safeguards bypassed in parts of the streaming API PUBLISHED

Description (CNA)

urllib3 is an HTTP client library for Python. From 2.6.0 to before 2.7.0, urllib3 could decompress the whole response instead of the requested portion (1) during the second HTTPResponse.read(amt=N) call when the response was decompressed using the official Brotli library or (2) when HTTPResponse.drain_conn() was called after the response had been read and decompressed partially (compression algorithm did not matter here). These issues could cause urllib3 to fully decode a small amount of highly compressed data in a single operation. This could result in excessive resource consumption (high CPU usage and massive memory allocation for the decompressed data) on the client side. This vulnerability is fixed in 2.7.0.

Affected (CNA)

Vendor / productVersions
urllib3 / urllib3affected >= 2.6.0, < 2.7.0

CWE

CWE-409

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.

redhat-SADP

A flaw was found in urllib3, an HTTP client library for Python. This vulnerability allows a remote attacker to cause excessive resource consumption, such as high CPU usage and massive memory allocation, on the client side. This occurs when urllib3 attempts to decompress an entire HTTP response, even if only a partial read was requested, or when draining the connection after a partial decompression. This can lead to a Denial of Service (DoS) condition.