CVE-2020-27720
Status: ModifiedHigh (7.5)—
On BIG-IP LTM/CGNAT version 16.0.0-16.0.0.1, 15.1.0-15.1.0.5, 14.1.0-14.1.3, and 13.1.0-13.1.3.5, when processing NAT66 traffic with Port Block Allocation (PBA) mode and SP-DAG enabled, and dag-ipv6-prefix-len configured with a value less than the default of 128, an undisclosed traffic pattern may cause the Traffic Management Microkernel (TMM) to restart.
CVSS
- Version: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Base score: 7.5
Exploitation probability (EPSS)
- Probability of exploitation in the next 30 days: 1.44%
- Percentile among all scored CVEs: 72
- Score date: 10/7/2026
EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).
Affected technologies (2)
CWEs
- NVD-CWE-noinfo
References
Raw JSON (NVD)
Show
{
"id": "CVE-2020-27720",
"cveTags": [],
"metrics": {
"cvssMetricV2": [
{
"type": "Primary",
"source": "nvd@nist.gov",
"cvssData": {
"version": "2.0",
"baseScore": 4.3,
"accessVector": "NETWORK",
"vectorString": "AV:N/AC:M/Au:N/C:N/I:N/A:P",
"authentication": "NONE",
"integrityImpact": "NONE",
"accessComplexity": "MEDIUM",
"availabilityImpact": "PARTIAL",
"confidentialityImpact": "NONE"
},
"acInsufInfo": false,
"impactScore": 2.9,
"baseSeverity": "MEDIUM",
"obtainAllPrivilege": false,
"exploitabilityScore": 8.6,
"obtainUserPrivilege": false,
"obtainOtherPrivilege": false,
"userInteractionRequired": false
}
],
"cvssMetricV31": [
{
"type": "Primary",
"source": "nvd@nist.gov",
"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:N/A:H",
"integrityImpact": "NONE",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
"privilegesRequired": "NONE",
"confidentialityImpact": "NONE"
},
"impactScore": 3.6,
"exploitabilityScore": 3.9
}
]
},
"affected": [
{
"source": "f5sirt@f5.com",
"affectedData": [
{
"vendor": "n/a",
"product": "BIG-IP LTM/CGNAT",
"versions": [
{
"status": "affected",
"version": "16.0.0-16.0.0.1, 15.1.0-15.1.0.5, 14.1.0-14.1.3, 13.1.0-13.1.3.5"
}
]
}
]
}
],
"published": "2020-12-24T16:15:15.087",
"references": [
{
"url": "https://support.f5.com/csp/article/K04048104",
"tags": [
"Vendor Advisory"
],
"source": "f5sirt@f5.com"
},
{
"url": "https://support.f5.com/csp/article/K04048104",
"tags": [
"Vendor Advisory"
],
"source": "af854a3a-2127-422b-91ae-364da2661108"
}
],
"vulnStatus": "Modified",
"weaknesses": [
{
"type": "Primary",
"source": "nvd@nist.gov",
"description": [
{
"lang": "en",
"value": "NVD-CWE-noinfo"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "On BIG-IP LTM/CGNAT version 16.0.0-16.0.0.1, 15.1.0-15.1.0.5, 14.1.0-14.1.3, and 13.1.0-13.1.3.5, when processing NAT66 traffic with Port Block Allocation (PBA) mode and SP-DAG enabled, and dag-ipv6-prefix-len configured with a value less than the default of 128, an undisclosed traffic pattern may cause the Traffic Management Microkernel (TMM) to restart."
},
{
"lang": "es",
"value": "En BIG-IP LTM/CGNAT versiones 16.0.0-16.0.0.1, 15.1.0-15.1.0.5, 14.1.0-14.1.3 y 13.1.0-13.1.3.5, cuando se procesa el tráfico NAT66 con Port Block Allocation (PBA) y SP-DAG habilitado, y dag-ipv6-prefix-len configurado con un valor menor que el predeterminado de 128, un patrón de tráfico no revelado puede causar que el Traffic Management Microkernel (TMM) se reinicie"
}
],
"lastModified": "2026-06-17T03:09:31.297",
"configurations": [
{
"nodes": [
{
"negate": false,
"cpeMatch": [
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"criteria": "cpe:2.3:a:f5:big-ip_carrier-grade_nat:*:*:*:*:*:*:*:*",
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"versionEndIncluding": "13.1.3",
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},
{
"criteria": "cpe:2.3:a:f5:big-ip_carrier-grade_nat:*:*:*:*:*:*:*:*",
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"matchCriteriaId": "F08EC455-D129-4B8F-B9D8-4A6E85B37217",
"versionEndExcluding": "14.1.3.1",
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{
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{
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{
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{
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},
{
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{
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"matchCriteriaId": "4F9D19B2-1D89-4917-A82E-289EDE52C68F",
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],
"operator": "OR"
}
]
}
],
"sourceIdentifier": "f5sirt@f5.com"
}