CVE-2026-81535
wolfSSH SSH client accepts unsolicited forwarded-tcpip channel opens without an authorization check
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.
| CWE | CWE-862 CWE-863 |
| Vendor | wolfssl inc. |
| Product | wolfssh |
| Published | Oct 7, 2026 |
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