Fix CVE(s): CVE-2026-59850
* SECURITY UPDATE: use-after-free in channel_rcv_data() when a DATA packet is received on a channel already closed by the remote peer - debian/patches/CVE-2026-59850.patch: reject DATA packets on channels already closed by the remote peer (SSH_CHANNEL_FLAG_CLOSED_REMOTE) in channel_rcv_data(), and additionally drop the callback list in ssh_channel_free() so DATA arriving between a local free and the peer's CLOSE can no longer dispatch callbacks on a released channel, both in src/channels.c - CVE-2026-59850
- Products
- libssh-4, libssh-dev, libssh-doc, libssh-gcrypt-4, libssh-gcrypt-dev
- Affected versions
- Not specified
- Fixed versions
- 0.8.0~20170825.94fa1e38-1ubuntu0.7+tuxcare.els6
- CVEs
- CVE-2026-59850
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 10:54 UTC · Revision 1
Source evidence
* SECURITY UPDATE: use-after-free in channel_rcv_data() when a DATA packet is received on a channel already closed by the remote peer - debian/patches/CVE-2026-59850.patch: reject DATA packets on channels already closed by the remote peer (SSH_CHANNEL_FLAG_CLOSED_REMOTE) in channel_rcv_data(), and additionally drop the callback list in ssh_channel_free() so DATA arriving between a local free and the peer's CLOSE can no longer dispatch callbacks on a released channel, both in src/channels.c - CVE-2026-59850
osv:CLSA-2026-1786092035
libssh-4
Fixed versions: 0.8.0~20170825.94fa1e38-1ubuntu0.7+tuxcare.els6
libssh-dev
Fixed versions: 0.8.0~20170825.94fa1e38-1ubuntu0.7+tuxcare.els6
libssh-doc
Fixed versions: 0.8.0~20170825.94fa1e38-1ubuntu0.7+tuxcare.els6
libssh-gcrypt-4
Fixed versions: 0.8.0~20170825.94fa1e38-1ubuntu0.7+tuxcare.els6
libssh-gcrypt-dev
Fixed versions: 0.8.0~20170825.94fa1e38-1ubuntu0.7+tuxcare.els6
Complete source record
{
"id": "a9c13e9f664dcc7af60f5e8f90a9e7dacfb0c7d3a3e17a63f0c44ce5ec7375ae",
"url": "https://osv.dev/vulnerability/CLSA-2026-1786092035",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "Fix CVE(s): CVE-2026-59850",
"summary": "* SECURITY UPDATE: use-after-free in channel_rcv_data() when a DATA packet is received on a channel already closed by the remote peer - debian/patches/CVE-2026-59850.patch: reject DATA packets on channels already closed by the remote peer (SSH_CHANNEL_FLAG_CLOSED_REMOTE) in channel_rcv_data(), and additionally drop the callback list in ssh_channel_free() so DATA arriving between a local free and the peer's CLOSE can no longer dispatch callbacks on a released channel, both in src/channels.c - CVE-2026-59850",
"evidence": "osv:CLSA-2026-1786092035",
"products": [
{
"name": {
"value": "libssh-4",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "0.8.0~20170825.94fa1e38-1ubuntu0.7+tuxcare.els6",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "libssh-dev",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "0.8.0~20170825.94fa1e38-1ubuntu0.7+tuxcare.els6",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "libssh-doc",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "0.8.0~20170825.94fa1e38-1ubuntu0.7+tuxcare.els6",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "libssh-gcrypt-4",
"evidence": "/affected/3/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "0.8.0~20170825.94fa1e38-1ubuntu0.7+tuxcare.els6",
"evidence": "/affected/3/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "libssh-gcrypt-dev",
"evidence": "/affected/4/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "0.8.0~20170825.94fa1e38-1ubuntu0.7+tuxcare.els6",
"evidence": "/affected/4/ranges"
}
],
"affected_versions": []
}
],
"severity": "unknown",
"structured": {
"id": "CLSA-2026-1786092035",
"aliases": [
"CLSA-2026-1786092035"
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "0.8.0~20170825.94fa1e38-1ubuntu0.7+tuxcare.els6"
}
]
}
],
"package": {
"name": "libssh-4",
"purl": "pkg:deb/tuxcare/libssh-4?distro=ubuntu-18.04",
"ecosystem": "TuxCare:Ubuntu:18.04"
},
"database_specific": {
"source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/ubuntu18.04els/CLSA-2026-1786092035.json"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "0.8.0~20170825.94fa1e38-1ubuntu0.7+tuxcare.els6"
}
]
}
],
"package": {
"name": "libssh-dev",
"purl": "pkg:deb/tuxcare/libssh-dev?distro=ubuntu-18.04",
"ecosystem": "TuxCare:Ubuntu:18.04"
},
"database_specific": {
"source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/ubuntu18.04els/CLSA-2026-1786092035.json"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "0.8.0~20170825.94fa1e38-1ubuntu0.7+tuxcare.els6"
}
]
}
],
"package": {
"name": "libssh-doc",
"purl": "pkg:deb/tuxcare/libssh-doc?distro=ubuntu-18.04",
"ecosystem": "TuxCare:Ubuntu:18.04"
},
"database_specific": {
"source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/ubuntu18.04els/CLSA-2026-1786092035.json"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "0.8.0~20170825.94fa1e38-1ubuntu0.7+tuxcare.els6"
}
]
}
],
"package": {
"name": "libssh-gcrypt-4",
"purl": "pkg:deb/tuxcare/libssh-gcrypt-4?distro=ubuntu-18.04",
"ecosystem": "TuxCare:Ubuntu:18.04"
},
"database_specific": {
"source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/ubuntu18.04els/CLSA-2026-1786092035.json"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "0.8.0~20170825.94fa1e38-1ubuntu0.7+tuxcare.els6"
}
]
}
],
"package": {
"name": "libssh-gcrypt-dev",
"purl": "pkg:deb/tuxcare/libssh-gcrypt-dev?distro=ubuntu-18.04",
"ecosystem": "TuxCare:Ubuntu:18.04"
},
"database_specific": {
"source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/ubuntu18.04els/CLSA-2026-1786092035.json"
}
}
],
"modified": "2026-10-26T09:31:34.051345438Z",
"provider": "osv",
"upstream": [
"CVE-2026-59850"
],
"references": [
"https://errata.tuxcare.com/els_os/ubuntu18.04els/CLSA-2026-1786092035.html",
"https://nvd.nist.gov/vuln/detail/CVE-2026-59850"
]
},
"related_cves": [
{
"value": "CVE-2026-59850",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": null
},
"source_id": "core-osv",
"document_id": 447751,
"published_at": "2026-08-07T08:40:44+00:00"
}