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.
CVE-2026-81535
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-81535
wolfSSH
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://github.com/wolfSSL/wolfssh",
"vendor": "wolfSSL Inc.",
"modules": [
"forwarding"
],
"product": "wolfSSH",
"versions": [
{
"status": "affected",
"changes": [
{
"at": "1.6.0",
"status": "unaffected"
}
],
"version": "1.4.8",
"versionType": "semver",
"lessThanOrEqual": "1.5.0"
}
],
"programFiles": [
"src/internal.c"
],
"defaultStatus": "unaffected"
}
]- Related CVEs
- CVE-2026-81535
Source reference:
/cveMetadata/cveId
Publisher severity
medium
Source reference: /containers/cna/metrics
- Event
- #12157 · Revision 1
- Added to Heist Feed
- Publisher date