Low
libreswan — security advisory
Libreswan in FIPS mode has a vulnerability where badly formed received certificates are rejected, but not deleted from the NSS cache. As a result, any real certificates with the same serial number are rejected as well. This can be abused to lock out legitimate peers from connecting. The add_decoded_cert() function missed a call to CERT_DestroyCertificate() due to an incorrect fix for CVE-2026-14957. Sending bogus certificates with new serial numbers could prevent the real certificates with those serial numbers from connecting until the service has restarted.
- Products
- libreswan
- Affected versions
- 3.20-7build1, 3.21-2, 3.22-1, 3.22-2, 3.22-3, 3.22-4, 3.23-1, 3.23-4, 3.29-2, 3.29-2build1, 3.32-3ubuntu3, 4.11-1ubuntu1, 4.12-1ubuntu1, 4.14-1ubuntu1, 4.14-1ubuntu2, 5.2-2.2ubuntu1, 5.2-2.2ubuntu2
- Fixed versions
- Not specified
- CVEs
- CVE-2026-77205
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 03:18 UTC · Revision 1
Source evidence
Libreswan in FIPS mode has a vulnerability where badly formed received certificates are rejected, but not deleted from the NSS cache. As a result, any real certificates with the same serial number are rejected as well. This can be abused to lock out legitimate peers from connecting. The add_decoded_cert() function missed a call to CERT_DestroyCertificate() due to an incorrect fix for CVE-2026-14957. Sending bogus certificates with new serial numbers could prevent the real certificates with those serial numbers from connecting until the service has restarted.
osv:UBUNTU-CVE-2026-77205
libreswan
Fixed versions: Not specified
libreswan
Fixed versions: Not specified
libreswan
Fixed versions: Not specified
libreswan
Fixed versions: Not specified
libreswan
Fixed versions: Not specified
libreswan
Fixed versions: Not specified
Complete source record
{
"id": "a7b19b87631e850d4fee5aa9176d6dfb9e0938d75d71ee8bfdb70949a186fb39",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-77205",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-77205",
"summary": "Libreswan in FIPS mode has a vulnerability where badly formed received certificates are rejected, but not deleted from the NSS cache. As a result, any real certificates with the same serial number are rejected as well. This can be abused to lock out legitimate peers from connecting. The add_decoded_cert() function missed a call to CERT_DestroyCertificate() due to an incorrect fix for CVE-2026-14957. Sending bogus certificates with new serial numbers could prevent the real certificates with those serial numbers from connecting until the service has restarted.",
"evidence": "osv:UBUNTU-CVE-2026-77205",
"products": [
{
"name": {
"value": "libreswan",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "3.20-7build1",
"evidence": "/affected/0/versions"
},
{
"value": "3.21-2",
"evidence": "/affected/0/versions"
},
{
"value": "3.22-1",
"evidence": "/affected/0/versions"
},
{
"value": "3.22-2",
"evidence": "/affected/0/versions"
},
{
"value": "3.22-3",
"evidence": "/affected/0/versions"
},
{
"value": "3.22-4",
"evidence": "/affected/0/versions"
},
{
"value": "3.23-1",
"evidence": "/affected/0/versions"
},
{
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},
{
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{
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{
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}
]
},
{
"name": {
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"evidence": "/affected/2/package/name"
},
"prerequisites": [],
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"affected_versions": [
{
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"evidence": "/affected/2/versions"
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},
{
"name": {
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"evidence": "/affected/3/package/name"
},
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"affected_versions": [
{
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"evidence": "/affected/3/versions"
},
{
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"evidence": "/affected/3/versions"
},
{
"value": "4.14-1ubuntu1",
"evidence": "/affected/3/versions"
},
{
"value": "4.14-1ubuntu2",
"evidence": "/affected/3/versions"
}
]
},
{
"name": {
"value": "libreswan",
"evidence": "/affected/4/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "5.2-2.2ubuntu2",
"evidence": "/affected/4/versions"
}
]
},
{
"name": {
"value": "libreswan",
"evidence": "/affected/5/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "5.2-2.2ubuntu1",
"evidence": "/affected/5/versions"
},
{
"value": "5.2-2.2ubuntu2",
"evidence": "/affected/5/versions"
}
]
}
],
"severity": "low",
"structured": {
"id": "UBUNTU-CVE-2026-77205",
"aliases": [
"UBUNTU-CVE-2026-77205"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L"
},
{
"type": "Ubuntu",
"score": "medium"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "libreswan",
"purl": "pkg:deb/ubuntu/libreswan?arch=source&distro=bionic",
"ecosystem": "Ubuntu:18.04:LTS"
},
"versions": [
"3.20-7build1",
"3.21-2",
"3.22-1",
"3.22-2",
"3.22-3",
"3.22-4",
"3.23-1",
"3.23-4"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-77205.json"
},
"ecosystem_specific": {
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{
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"binary_version": "3.23-4"
}
]
}
},
{
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{
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"package": {
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"ecosystem": "Ubuntu:20.04:LTS"
},
"versions": [
"3.29-2",
"3.29-2build1"
],
"database_specific": {
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},
"ecosystem_specific": {
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]
}
},
{
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],
"package": {
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"purl": "pkg:deb/ubuntu/libreswan?arch=source&distro=jammy",
"ecosystem": "Ubuntu:22.04:LTS"
},
"versions": [
"3.32-3ubuntu3"
],
"database_specific": {
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},
"ecosystem_specific": {
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}
]
}
},
{
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],
"package": {
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"ecosystem": "Ubuntu:24.04:LTS"
},
"versions": [
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"4.12-1ubuntu1",
"4.14-1ubuntu1",
"4.14-1ubuntu2"
],
"database_specific": {
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},
"ecosystem_specific": {
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{
"binary_name": "libreswan",
"binary_version": "4.14-1ubuntu2"
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]
}
},
{
"ranges": [
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],
"package": {
"name": "libreswan",
"purl": "pkg:deb/ubuntu/libreswan?arch=source&distro=stonking",
"ecosystem": "Ubuntu:26.10"
},
"versions": [
"5.2-2.2ubuntu2"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-77205.json"
},
"ecosystem_specific": {
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{
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]
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},
{
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"type": "ECOSYSTEM",
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],
"package": {
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"purl": "pkg:deb/ubuntu/libreswan?arch=source&distro=resolute",
"ecosystem": "Ubuntu:26.04:LTS"
},
"versions": [
"5.2-2.2ubuntu1",
"5.2-2.2ubuntu2"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-77205.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libreswan",
"binary_version": "5.2-2.2ubuntu2"
}
]
}
}
],
"modified": "2026-10-17T13:01:07.367756344Z",
"provider": "osv",
"upstream": [
"CVE-2026-77205"
],
"references": [
"https://ubuntu.com/security/CVE-2026-77205",
"https://www.cve.org/CVERecord?id=CVE-2026-77205",
"https://libreswan.org/security/CVE-2026-14957/CVE-2026-14957.txt",
"https://libreswan.org/security/CVE-2026-77205/",
"https://libreswan.org/security/CVE-2026-77205/CVE-2026-77205.txt"
]
},
"related_cves": [
{
"value": "CVE-2026-77205",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 361020,
"published_at": "2026-10-13T22:18:00+00:00"
}