Improper handling of highly compressed data in urllib3 - CVE-2026-44432
Published: May 9, 2026
Vulnerability identifier: #VU130906
CSH Severity: Medium
CVSSv4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-44432
CWE-ID: CWE-409
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerable software:
urllib3
urllib3
Software vendor:
urlib3
urlib3
Description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to improper handling of highly compressed data in the urllib3 streaming API when processing compressed HTTP responses from untrusted sources. A remote attacker can send a highly compressed response to cause a denial of service.
Exploitation requires either incremental reads of a Brotli-encoded response with at least two read or stream calls while using the official Brotli library, or calling HTTPResponse.drain_conn() after decompression has already started.
Remediation
Install security update from vendor's website.