CVE-2026-40198
Net::CIDR::Lite versions before 0.23 for Perl does not validate IPv6 group count, which may allow IP ACL bypass.
_pack_ipv6() does not check that uncompressed IPv6 addresses (without ::) have exactly 8 hex groups. Inputs like "abcd", "1:2:3", or "1:2:3:4:5:6:7" are accepted and produce packed values of wrong length (3, 7, or 15 bytes instead of 17).
The packed values are used internally for mask and comparison operations. find() and bin_find() use Perl string comparison (lt/gt) on these values, and comparing strings of different lengths gives wrong results. This can cause find() to incorrectly report an address as inside or outside a range.
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Example:
This is the same class of input validation issue as CVE-2021-47154 (IPv4 leading zeros) previously fixed in this module.
See also CVE-2026-40199, a related issue in the same function affecting IPv4 mapped IPv6 addresses.
Detalles técnicos trazas, registros y código del informe original
my $cidr = Net::CIDR::Lite->new("::/8");
$cidr->find("1:2:3"); # invalid input, incorrectly returns trueCVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- Puntuación base: 7.5
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.51%
- Percentil entre todas las CVEs puntuadas: 42
- Fecha de la puntuación: 6/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
🎯 Técnicas ATT&CK
Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.
- Explotación
T1190Exploit Public-Facing Applicationinitial access60 %
Inferido por reglas deterministas a partir del vector CVSS y la CWE. Solo orientativo.
🛡️ Mitigaciones ATT&CK que cubren estas técnicas
Tecnologías afectadas (1)
CWE
- CWE-1286
Referencias
JSON original (NVD)
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{
"id": "CVE-2026-40198",
"cveTags": [],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-40198",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "none"
},
{
"automatable": "yes"
},
{
"technicalImpact": "partial"
}
],
"version": "2.0.3",
"timestamp": "2026-04-13T14:41:19.772152Z"
}
}
],
"cvssMetricV31": [
{
"type": "Secondary",
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 7.5,
"attackVector": "NETWORK",
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
"integrityImpact": "HIGH",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "NONE",
"privilegesRequired": "NONE",
"confidentialityImpact": "NONE"
},
"impactScore": 3.6,
"exploitabilityScore": 3.9
}
]
},
"affected": [
{
"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
"affectedData": [
{
"repo": "https://github.com/stigtsp/Net-CIDR-Lite",
"vendor": "STIGTSP",
"product": "Net::CIDR::Lite",
"versions": [
{
"status": "affected",
"version": "0",
"lessThan": "0.23",
"versionType": "custom"
}
],
"packageName": "Net-CIDR-Lite",
"programFiles": [
"Lite.pm"
],
"collectionURL": "https://cpan.org/modules",
"defaultStatus": "unaffected",
"programRoutines": [
{
"name": "Net::CIDR::Lite::_pack_ipv6"
}
]
}
]
}
],
"published": "2026-04-10T22:16:21.463",
"references": [
{
"url": "https://github.com/stigtsp/Net-CIDR-Lite/commit/25d65f85dbe4885959a10471725ec9d250a589c3.patch",
"tags": [
"Patch"
],
"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"
},
{
"url": "https://metacpan.org/release/STIGTSP/Net-CIDR-Lite-0.23/changes",
"tags": [
"Release Notes"
],
"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"
},
{
"url": "https://www.cve.org/CVERecord?id=CVE-2026-40199",
"tags": [
"Third Party Advisory"
],
"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"
}
],
"vulnStatus": "Analyzed",
"weaknesses": [
{
"type": "Secondary",
"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
"description": [
{
"lang": "en",
"value": "CWE-1286"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "Net::CIDR::Lite versions before 0.23 for Perl does not validate IPv6 group count, which may allow IP ACL bypass.\n\n_pack_ipv6() does not check that uncompressed IPv6 addresses (without ::) have exactly 8 hex groups. Inputs like \"abcd\", \"1:2:3\", or \"1:2:3:4:5:6:7\" are accepted and produce packed values of wrong length (3, 7, or 15 bytes instead of 17).\n\nThe packed values are used internally for mask and comparison operations. find() and bin_find() use Perl string comparison (lt/gt) on these values, and comparing strings of different lengths gives wrong results. This can cause find() to incorrectly report an address as inside or outside a range.\n\nExample:\n\n my $cidr = Net::CIDR::Lite->new(\"::/8\");\n $cidr->find(\"1:2:3\"); # invalid input, incorrectly returns true\n\nThis is the same class of input validation issue as CVE-2021-47154 (IPv4 leading zeros) previously fixed in this module.\n\nSee also CVE-2026-40199, a related issue in the same function affecting IPv4 mapped IPv6 addresses."
}
],
"lastModified": "2026-06-17T10:44:51.610",
"configurations": [
{
"nodes": [
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:a:stigtsp:net\\:\\:cidr\\:\\:lite:*:*:*:*:*:perl:*:*",
"vulnerable": true,
"matchCriteriaId": "2B8C0BC5-5E3C-4399-9FD6-437BFF65130F",
"versionEndExcluding": "0.23"
}
],
"operator": "OR"
}
]
}
],
"sourceIdentifier": "9b29abf9-4ab0-4765-b253-1875cd9b441e"
}