stunnel 4.21 through 4.54, when CONNECT protocol negotiation and NTLM authentication are enabled, does not correctly perform integer conversion, which allows remote proxy servers to execute arbitrary code via a crafted request that triggers a buffer overflow.
CVSS Severity (version 2.0):
Impact Subscore: 8.5
Exploitability Subscore: 4.9
CVSS Version 2 Metrics:
Access Vector: Network exploitable
Access Complexity: High
Authentication: Not required to exploit
Impact Type: Allows unauthorized disclosure of information; Allows unauthorized modification; Allows disruption of service
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