Medium
krb5 — security advisory
MIT krb5 through 1.22.2 contains a NULL pointer dereference vulnerability in the KDC's get_pac_princ_with_realm() that returns success while leaving the client principal NULL on malformed names. A malicious or compromised cross-realm trusted KDC can send an S4U2Proxy request with a PAC carrying a malformed client name to crash krb5kdc and deny authentication.
- Products
- krb5
- Affected versions
- 1.20.1-2, 1.20.1-2+deb12u1, 1.20.1-2+deb12u2, 1.20.1-2+deb12u3, 1.20.1-2+deb12u4, 1.20.1-2+deb12u5, 1.20.1-2+loong64, 1.20.1-3, 1.20.1-4, 1.20.1-5, 1.20.1-5.1, 1.20.1-5.1~exp1, 1.20.1-6, 1.21.2-1, 1.21.3-1, 1.21.3-2, 1.21.3-3, 1.21.3-4, 1.21.3-5, 1.21.3-5+deb13u1, 1.22.1-1, 1.22.1-2, 1.22.1-2.1, 1.22.1-3
- Fixed versions
- Not specified
- CVEs
- CVE-2026-107708
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 30 Oct 2026, 11:48 UTC · Revision 1
Source evidence
MIT krb5 through 1.22.2 contains a NULL pointer dereference vulnerability in the KDC's get_pac_princ_with_realm() that returns success while leaving the client principal NULL on malformed names. A malicious or compromised cross-realm trusted KDC can send an S4U2Proxy request with a PAC carrying a malformed client name to crash krb5kdc and deny authentication.
osv:DEBIAN-CVE-2026-107708
krb5
Fixed versions: Not specified
krb5
Fixed versions: Not specified
krb5
Fixed versions: Not specified
Complete source record
{
"id": "9c733459f077facb89aab648d3866e889249c5ca81eacf6d924d18340011e6ef",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-107708",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-107708",
"summary": "MIT krb5 through 1.22.2 contains a NULL pointer dereference vulnerability in the KDC's get_pac_princ_with_realm() that returns success while leaving the client principal NULL on malformed names. A malicious or compromised cross-realm trusted KDC can send an S4U2Proxy request with a PAC carrying a malformed client name to crash krb5kdc and deny authentication.",
"evidence": "osv:DEBIAN-CVE-2026-107708",
"products": [
{
"name": {
"value": "krb5",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1.20.1-2",
"evidence": "/affected/0/versions"
},
{
"value": "1.20.1-2+deb12u1",
"evidence": "/affected/0/versions"
},
{
"value": "1.20.1-2+deb12u2",
"evidence": "/affected/0/versions"
},
{
"value": "1.20.1-2+deb12u3",
"evidence": "/affected/0/versions"
},
{
"value": "1.20.1-2+deb12u4",
"evidence": "/affected/0/versions"
},
{
"value": "1.20.1-2+deb12u5",
"evidence": "/affected/0/versions"
},
{
"value": "1.20.1-2+loong64",
"evidence": "/affected/0/versions"
},
{
"value": "1.20.1-3",
"evidence": "/affected/0/versions"
},
{
"value": "1.20.1-4",
"evidence": "/affected/0/versions"
},
{
"value": "1.20.1-5",
"evidence": "/affected/0/versions"
},
{
"value": "1.20.1-5.1",
"evidence": "/affected/0/versions"
},
{
"value": "1.20.1-5.1~exp1",
"evidence": "/affected/0/versions"
},
{
"value": "1.20.1-6",
"evidence": "/affected/0/versions"
},
{
"value": "1.21.2-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.21.3-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.21.3-2",
"evidence": "/affected/0/versions"
},
{
"value": "1.21.3-3",
"evidence": "/affected/0/versions"
},
{
"value": "1.21.3-4",
"evidence": "/affected/0/versions"
},
{
"value": "1.21.3-5",
"evidence": "/affected/0/versions"
},
{
"value": "1.22.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.22.1-2",
"evidence": "/affected/0/versions"
},
{
"value": "1.22.1-2.1",
"evidence": "/affected/0/versions"
},
{
"value": "1.22.1-3",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "krb5",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1.21.3-5",
"evidence": "/affected/1/versions"
},
{
"value": "1.21.3-5+deb13u1",
"evidence": "/affected/1/versions"
},
{
"value": "1.22.1-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.22.1-2",
"evidence": "/affected/1/versions"
},
{
"value": "1.22.1-2.1",
"evidence": "/affected/1/versions"
},
{
"value": "1.22.1-3",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "krb5",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1.21.3-5",
"evidence": "/affected/2/versions"
},
{
"value": "1.22.1-1",
"evidence": "/affected/2/versions"
},
{
"value": "1.22.1-2",
"evidence": "/affected/2/versions"
},
{
"value": "1.22.1-2.1",
"evidence": "/affected/2/versions"
},
{
"value": "1.22.1-3",
"evidence": "/affected/2/versions"
}
]
}
],
"severity": "medium",
"structured": {
"id": "DEBIAN-CVE-2026-107708",
"aliases": [
"DEBIAN-CVE-2026-107708"
],
"metrics": [
{
"type": "CVSS_V4",
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "krb5",
"purl": "pkg:deb/debian/krb5?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"1.20.1-2",
"1.20.1-2+deb12u1",
"1.20.1-2+deb12u2",
"1.20.1-2+deb12u3",
"1.20.1-2+deb12u4",
"1.20.1-2+deb12u5",
"1.20.1-2+loong64",
"1.20.1-3",
"1.20.1-4",
"1.20.1-5",
"1.20.1-5.1",
"1.20.1-5.1~exp1",
"1.20.1-6",
"1.21.2-1",
"1.21.3-1",
"1.21.3-2",
"1.21.3-3",
"1.21.3-4",
"1.21.3-5",
"1.22.1-1",
"1.22.1-2",
"1.22.1-2.1",
"1.22.1-3"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-107708.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "krb5",
"purl": "pkg:deb/debian/krb5?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"1.21.3-5",
"1.21.3-5+deb13u1",
"1.22.1-1",
"1.22.1-2",
"1.22.1-2.1",
"1.22.1-3"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-107708.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "krb5",
"purl": "pkg:deb/debian/krb5?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"1.21.3-5",
"1.22.1-1",
"1.22.1-2",
"1.22.1-2.1",
"1.22.1-3"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-107708.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-14T10:00:29.164236497Z",
"provider": "osv",
"upstream": [
"CVE-2026-107708"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-107708"
]
},
"related_cves": [
{
"value": "CVE-2026-107708",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 315372,
"published_at": "2026-10-08T21:17:52.223+00:00"
}