CVE-2026-70368: Mobi-Com Polska Sp. Z O.o Stunnel

Medium severity, CVSS 6.5. EPSS: 0.4% chance of exploitation in the next 30 days.

A stack-based out-of-bounds read vulnerability exists in the "s_vlog" function of stunnel, when handling oversized log messages via "vsnprintf". A remote attacker with network access to a stunnel service can send protocol inputs that trigger a log message longer than 1024 bytes, leading to an out-of-bounds stack read and a potential crash. In certain corner cases, the same vulnerability could be used to replace a series of trailing "\n" characters with "\0".

Affected products

• Mobi-Com Polska Sp. Z O.o Stunnel: from 5.68, before 5.80 (fixed in 5.80)
• Red Hat Red Hat Enterprise Linux 10
• Red Hat Red Hat Enterprise Linux 6
• Red Hat Red Hat Enterprise Linux 7
• Red Hat Red Hat Enterprise Linux 8
• Red Hat Red Hat Enterprise Linux 9

Published 2026-08-04. Last modified 2026-08-06.