libssh — security advisory
A flaw was found in libssh when using the ChaCha20 cipher with the OpenSSL library. If an attacker manages to exhaust the heap space, this error is not detected and may lead to libssh using a partially initialized cipher context. This occurs because the OpenSSL error code returned aliases with the SSH_OK code, resulting in libssh not properly detecting the error returned by the OpenSSL library. This issue can lead to undefined behavior, including compromised data confidentiality and integrity or crashes.
- Products
- libssh
- Affected versions
- 0.10.5-2, 0.10.5-3, 0.10.5-3+hurd.1, 0.10.6-0+deb12u1
- Fixed versions
- 0.10.6-0+deb12u2, 0.11.2-1
- CVEs
- CVE-2025-5987
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 23:08 UTC · Revision 1
Source evidence
A flaw was found in libssh when using the ChaCha20 cipher with the OpenSSL library. If an attacker manages to exhaust the heap space, this error is not detected and may lead to libssh using a partially initialized cipher context. This occurs because the OpenSSL error code returned aliases with the SSH_OK code, resulting in libssh not properly detecting the error returned by the OpenSSL library. This issue can lead to undefined behavior, including compromised data confidentiality and integrity or crashes.
osv:DEBIAN-CVE-2025-5987
libssh
Fixed versions: 0.10.6-0+deb12u2
libssh
Fixed versions: 0.11.2-1
libssh
Fixed versions: 0.11.2-1
Complete source record
{
"id": "dd7216d530b09ef894ed7870f18d198c8febc09e1879f52dbd40fb23212a505f",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2025-5987",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2025-5987",
"summary": "A flaw was found in libssh when using the ChaCha20 cipher with the OpenSSL library. If an attacker manages to exhaust the heap space, this error is not detected and may lead to libssh using a partially initialized cipher context. This occurs because the OpenSSL error code returned aliases with the SSH_OK code, resulting in libssh not properly detecting the error returned by the OpenSSL library. This issue can lead to undefined behavior, including compromised data confidentiality and integrity or crashes.",
"evidence": "osv:DEBIAN-CVE-2025-5987",
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{
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"evidence": "/affected/0/versions"
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"affected": [
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"versions": [
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"0.10.5-3",
"0.10.5-3+hurd.1",
"0.10.6-0+deb12u1"
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"ecosystem_specific": {
"urgency": "not yet assigned"
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{
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"package": {
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"purl": "pkg:deb/debian/libssh?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2025-5987.json"
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{
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"package": {
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},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2025-5987.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-23T17:47:35.758399980Z",
"provider": "osv",
"upstream": [
"CVE-2025-5987"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2025-5987"
]
},
"related_cves": [
{
"value": "CVE-2025-5987",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 417838,
"published_at": "2025-07-07T15:15:28.18+00:00"
}