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vuln-cve/data/2026/66xxx/CVE-2026-66035.json
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{
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"cveMetadata": {
"cveId": "CVE-2026-66035",
"assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
"state": "PUBLISHED",
"assignerShortName": "VulnCheck",
"dateReserved": "2026-07-23T20:45:17.816Z",
"datePublished": "2026-07-24T16:45:24.405Z",
"dateUpdated": "2026-07-28T01:06:26.873Z"
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"dateUpdated": "2026-07-28T01:06:26.873Z"
},
"title": "libssh2 Heap Buffer Overflow via ETM Cipher Negotiation",
"descriptions": [
{
"lang": "en",
"value": "libssh2 through 1.11.1, fixed in commit 42e33d8, contains a pre-authentication heap buffer overflow vulnerability that allows a malicious SSH server to corrupt heap metadata in any connecting client by sending a packet with a packet_length smaller than the cipher's block size during Encrypt-then-MAC cipher negotiation. In the fullpacket() function in src/transport.c, the ETM path allocates a buffer of packet_length bytes but copies blocksize minus one bytes via memcpy, causing an overflow that on 32-bit glibc writes attacker-controlled bytes into an adjacent chunk's SIZE field, enabling tcache bin confusion, overlapping live objects, and function pointer overwrite during the session handshake before authentication."
}
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"datePublic": "2026-07-03T00:00:00.000Z",
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"cweId": "CWE-122",
"description": "Heap-based Buffer Overflow",
"type": "CWE"
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"version": "0",
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"version": "42e33d81577ed4b95d4b4f6f845e5ee8efe5eeb4",
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"attackRequirements": "NONE",
"privilegesRequired": "NONE",
"userInteraction": "PASSIVE",
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"subConfidentialityImpact": "NONE",
"vulnIntegrityImpact": "HIGH",
"subIntegrityImpact": "NONE",
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"Safety": "NOT_DEFINED",
"Automatable": "NOT_DEFINED",
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"vulnerabilityResponseEffort": "NOT_DEFINED",
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},
{
"url": "https://www.vulncheck.com/advisories/libssh2-heap-buffer-overflow-via-etm-cipher-negotiation",
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}
],
"credits": [
{
"lang": "en",
"value": "VladimirEliTokarev",
"type": "finder"
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"source": {
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"options": [
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{
"Automatable": "no"
},
{
"Technical Impact": "total"
}
],
"role": "CISA Coordinator",
"version": "2.0.3",
"id": "CVE-2026-66035"
}
}
}
],
"title": "CISA ADP Vulnrichment",
"providerMetadata": {
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"dateUpdated": "2026-07-25T03:55:52.526Z"
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}
}