CVE-2013-1762: Stunnel

Medium severity, CVSS 6.6. EPSS: 2.9% chance of exploitation in the next 30 days.

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.

Affected products

• Stunnel Stunnel: up to and including 4.54; version 4.21 only; version 4.22 only; version 4.23 only; version 4.24 only; version 4.25 only; …

Published 2013-03-08. Last modified 2026-06-16.