DEBIAN-CVE-2026-66034
libssh2 through 1.11.1, fixed in commit a13bb6c, contains a missing bounds check vulnerability that allows a malicious SSH server to trigger an arbitrary-length heap out-of-bounds read and a free of an uninitialized pointer via the publickey subsystem. In libssh2_publickey_list_fetch(), the version 1 response parser reads a server-controlled comment_len value and advances the parse pointer without verifying sufficient bytes remain in the buffer, causing the out-of-bounds read to leak heap pointers from adjacent allocations defeating ASLR, followed by heap allocator state corruption when the error cleanup path frees an uninitialized pointer from a non-zeroed realloc() region.
DEBIAN-CVE-2026-66034
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: osv:DEBIAN-CVE-2026-66034
libssh2
Source reference: /affected/0/package/name
- Affected versions
- 1.10.0-3
Source reference:
/affected/0/versions - Fixed versions
- 1.10.0-3+deb12u1
Source reference:
/affected/0/ranges - Prerequisites
- Not stated in this record
libssh2
Source reference: /affected/1/package/name
- Affected versions
- 1.11.1-1
Source reference:
/affected/1/versions1.11.1-1+deb13u1Source reference:
/affected/1/versions - Fixed versions
- 1.11.1-1+deb13u2
Source reference:
/affected/1/ranges - Prerequisites
- Not stated in this record
libssh2
Source reference: /affected/2/package/name
- Affected versions
- 1.11.1-1
Source reference:
/affected/2/versions1.11.1-2Source reference:
/affected/2/versions1.11.1-3Source reference:
/affected/2/versions1.11.1-4Source reference:
/affected/2/versions - Fixed versions
- 1.11.1-5
Source reference:
/affected/2/ranges - Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1.10.0-3+deb12u1"
}
]
}
],
"package": {
"name": "libssh2",
"purl": "pkg:deb/debian/libssh2?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"1.10.0-3"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-66034.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1.11.1-1+deb13u2"
}
]
}
],
"package": {
"name": "libssh2",
"purl": "pkg:deb/debian/libssh2?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"1.11.1-1",
"1.11.1-1+deb13u1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-66034.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1.11.1-5"
}
]
}
],
"package": {
"name": "libssh2",
"purl": "pkg:deb/debian/libssh2?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"1.11.1-1",
"1.11.1-2",
"1.11.1-3",
"1.11.1-4"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-66034.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
]Publisher severity
No explicit severity was provided.
- Event
- #58157 · Revision 1
- Added to Heist Feed
- Publisher date