CVE-2026-81535: wolfSSL Inc Wolfssh

Medium severity, CVSS 6.3. EPSS: 0.3% chance of exploitation in the next 30 days.

In wolfSSH through 1.5.0 built with --enable-fwd, DoChannelOpen() in src/internal.c gates only direct-tcpip channel opens with the forwarding policy callback. forwarded-tcpip opens are admitted without an authorization check and are not capped in number, allowing a malicious SSH peer to make an endpoint allocate unbounded per-channel buffers for forwarding channels the application never authorized. A client also does not check a forwarded-tcpip open against the forwards it registered with a tcpip-forward request, as RFC 4254 section 7.2 requires, so a malicious server can open forwarding channels for addresses and ports the client never asked it to forward.

Affected products

• wolfSSL Inc Wolfssh: from 1.4.8, up to and including 1.5.0

Published 2026-10-07. Last modified 2026-10-07.