{"id":"CVE-2026-81535","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-81535","summary":"wolfSSH SSH client accepts unsolicited forwarded-tcpip channel opens without an authorization check","details":"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.","published":"2026-10-07T02:39:27.830Z","modified":"2026-10-13T02:47:02.242219370Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[],"fix":{"url":"https://github.com/wolfSSL/wolfssh/commit/616eb681e70759c30c3ba158f2b18d7bd954def8","label":"wolfSSL/wolfssh@616eb68"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/81xxx/CVE-2026-81535.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-81535"},{"type":"FIX","url":"https://github.com/wolfSSL/wolfssh/commit/616eb681e70759c30c3ba158f2b18d7bd954def8"},{"type":"FIX","url":"https://github.com/wolfSSL/wolfssh/commit/79a7f299337a28aa561409688a268d0efe6e295c"},{"type":"FIX","url":"https://github.com/wolfSSL/wolfssh/commit/e396a0a4b6b367f10270287446a4be0071742b5c"},{"type":"PACKAGE","url":"https://github.com/wolfSSL/wolfssh"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-13T02:47:02.242219370Z"}}