CVE-2026-81535
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.
CVSS
- Versión: 4.0
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- Puntuación base: 6.3
Probabilidad de explotación (EPSS)
FIRST aún no ha puntuado esta CVE (habitual en CVEs muy recientes o rechazadas).
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
🎯 Técnicas ATT&CK
Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.
- Explotación
T1190Exploit Public-Facing Applicationinitial access60 % - Impacto principal
T1078Valid Accountsstealth · persistence · privilege escalation · initial access55 %
Inferido por reglas deterministas a partir del vector CVSS y la CWE. Solo orientativo.
🛡️ Mitigaciones ATT&CK que cubren estas técnicas
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
CWE
- CWE-862, CWE-863
Referencias
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-81535",
"cveTags": [],
"metrics": {
"cvssMetricV40": [
{
"type": "Secondary",
"source": "facts@wolfssl.com",
"cvssData": {
"Safety": "NOT_DEFINED",
"version": "4.0",
"Recovery": "NOT_DEFINED",
"baseScore": 6.3,
"Automatable": "NOT_DEFINED",
"attackVector": "NETWORK",
"baseSeverity": "MEDIUM",
"valueDensity": "NOT_DEFINED",
"vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"exploitMaturity": "NOT_DEFINED",
"providerUrgency": "NOT_DEFINED",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"attackRequirements": "PRESENT",
"privilegesRequired": "NONE",
"subIntegrityImpact": "NONE",
"vulnIntegrityImpact": "NONE",
"integrityRequirement": "NOT_DEFINED",
"modifiedAttackVector": "NOT_DEFINED",
"subAvailabilityImpact": "NONE",
"vulnAvailabilityImpact": "LOW",
"availabilityRequirement": "NOT_DEFINED",
"modifiedUserInteraction": "NOT_DEFINED",
"modifiedAttackComplexity": "NOT_DEFINED",
"subConfidentialityImpact": "NONE",
"vulnConfidentialityImpact": "NONE",
"confidentialityRequirement": "NOT_DEFINED",
"modifiedAttackRequirements": "NOT_DEFINED",
"modifiedPrivilegesRequired": "NOT_DEFINED",
"modifiedSubIntegrityImpact": "NOT_DEFINED",
"modifiedVulnIntegrityImpact": "NOT_DEFINED",
"vulnerabilityResponseEffort": "NOT_DEFINED",
"modifiedSubAvailabilityImpact": "NOT_DEFINED",
"modifiedVulnAvailabilityImpact": "NOT_DEFINED",
"modifiedSubConfidentialityImpact": "NOT_DEFINED",
"modifiedVulnConfidentialityImpact": "NOT_DEFINED"
}
}
]
},
"affected": [
{
"source": "facts@wolfssl.com",
"affectedData": [
{
"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"
}
]
}
],
"published": "2026-10-07T03:16:59.567",
"references": [
{
"url": "https://github.com/wolfSSL/wolfssh/commit/616eb681e70759c30c3ba158f2b18d7bd954def8",
"source": "facts@wolfssl.com"
},
{
"url": "https://github.com/wolfSSL/wolfssh/commit/79a7f299337a28aa561409688a268d0efe6e295c",
"source": "facts@wolfssl.com"
},
{
"url": "https://github.com/wolfSSL/wolfssh/commit/e396a0a4b6b367f10270287446a4be0071742b5c",
"source": "facts@wolfssl.com"
}
],
"vulnStatus": "Received",
"weaknesses": [
{
"type": "Secondary",
"source": "facts@wolfssl.com",
"description": [
{
"lang": "en",
"value": "CWE-862"
},
{
"lang": "en",
"value": "CWE-863"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "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."
}
],
"lastModified": "2026-10-07T03:16:59.567",
"sourceIdentifier": "facts@wolfssl.com"
}