Improper Certificate Validation in urllib3 - #VU150185
Published: September 16, 2026 / Updated: September 18, 2026
Vulnerability identifier: #VU150185
CSH Severity: Medium
CVSS v4: 7 [CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-295
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to disclose sensitive information and modify forwarded requests and responses.
The vulnerability exists due to improper certificate validation in the HTTPS proxy TLS configuration when handling TLS connections to HTTPS proxies. A remote attacker can impersonate an HTTPS proxy using a certificate accepted under the effective proxy TLS policy to disclose sensitive information and modify forwarded requests and responses.
Exploitation requires intercepting the connection to an HTTPS proxy.
Affected software
urllib3
Remediation
Install security update from vendor's website.
urllib3 - update to 2.8.0