openssh — security advisory
OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kex_algorithms handling. This is fixed in OpenSSH 9.2. The double free can be leveraged, by an unauthenticated remote attacker in the default configuration, to jump to any location in the sshd address space. One third-party report states "remote code execution is theoretically possible."
- Products
- openssh
- Affected versions
- Not specified
- Fixed versions
- 1:9.2p1-1
- CVEs
- CVE-2023-25136
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 15:45 UTC · Revision 1
Source evidence
OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kex_algorithms handling. This is fixed in OpenSSH 9.2. The double free can be leveraged, by an unauthenticated remote attacker in the default configuration, to jump to any location in the sshd address space. One third-party report states "remote code execution is theoretically possible."
osv:DEBIAN-CVE-2023-25136
openssh
Fixed versions: 1:9.2p1-1
openssh
Fixed versions: 1:9.2p1-1
openssh
Fixed versions: 1:9.2p1-1
Complete source record
{
"id": "c7c0cb0b07149c3a04169f06742685f188a848fb7fb76024d2c986fca4e7d11b",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2023-25136",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2023-25136",
"summary": "OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kex_algorithms handling. This is fixed in OpenSSH 9.2. The double free can be leveraged, by an unauthenticated remote attacker in the default configuration, to jump to any location in the sshd address space. One third-party report states \"remote code execution is theoretically possible.\"",
"evidence": "osv:DEBIAN-CVE-2023-25136",
"products": [
{
"name": {
"value": "openssh",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1:9.2p1-1",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": []
},
{
"name": {
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"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
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"evidence": "/affected/1/ranges"
}
],
"affected_versions": []
},
{
"name": {
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}
],
"affected_versions": []
}
],
"severity": "medium",
"structured": {
"id": "DEBIAN-CVE-2023-25136",
"aliases": [
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],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H"
}
],
"affected": [
{
"ranges": [
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"events": [
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],
"package": {
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"purl": "pkg:deb/debian/openssh?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2023-25136.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
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"events": [
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{
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],
"package": {
"name": "openssh",
"purl": "pkg:deb/debian/openssh?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2023-25136.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
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"events": [
{
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{
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],
"package": {
"name": "openssh",
"purl": "pkg:deb/debian/openssh?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2023-25136.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-26T18:01:37.169158696Z",
"provider": "osv",
"upstream": [
"CVE-2023-25136"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2023-25136"
]
},
"related_cves": [
{
"value": "CVE-2023-25136",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 455602,
"published_at": "2023-02-03T06:15:09.35+00:00"
}