CVE-2026-75943 (GCVE-0-2026-75943)
Vulnerability from cvelistv5 – Published: 2026-09-14 22:11 – Updated: 2026-09-14 22:11
VLAI
EPSS
VEX
Title
A brief (milliseconds to seconds) traffic leak may occur when an authenticated supplicant is removed, either via the clear dot1x host all CLI command or due to a supplicant timeout. During this window, the supplicant's traffic may pass without ACL enforcem
Summary
A brief (milliseconds to seconds) traffic leak may occur when an authenticated supplicant is removed, either via the clear dot1x host all CLI command or due to a supplicant timeout. During this window, the supplicant's traffic may pass without ACL enforcement.
Severity
CWE
- CWE-459 - Incomplete Cleanup
Assigner
References
1 reference
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Arista Networks | EOS |
Affected:
4.36.0 , ≤ 4.36.1F
(custom)
Affected: 4.35.0 , ≤ 4.35.5M (custom) Affected: 4.34.0 , ≤ 4.34.7.1M (custom) Affected: 0.0.0 , ≤ 4.33.9M (custom) |
guessed |
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "EOS",
"vendor": "Arista Networks",
"versions": [
{
"lessThanOrEqual": "4.36.1F",
"status": "affected",
"version": "4.36.0",
"versionType": "custom"
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{
"lessThanOrEqual": "4.35.5M",
"status": "affected",
"version": "4.35.0",
"versionType": "custom"
},
{
"lessThanOrEqual": "4.34.7.1M",
"status": "affected",
"version": "4.34.0",
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{
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"status": "affected",
"version": "0.0.0",
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"configurations": [
{
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"value": "\u003cpre\u003e\u003cp\u003eIn order to be vulnerable to any of the vulnerabilities, the following condition must be met under interface configuration mode:\u003c/p\u003e\u003col\u003e\u003cli\u003e802.1X (dot1x in the CLI) must be configured with \u003cb\u003epae authenticator\u003c/b\u003e\u003cdiv\u003e\u0026nbsp;\u003c/div\u003e\u003c/li\u003e\u003cli\u003eport-control must be set to auto mode\u003cdiv\u003e\u0026nbsp;\u003c/div\u003e\u003c/li\u003e\u003cli\u003eA static or dynamic ACL must be configured.\u003cdiv\u003e\u0026nbsp;\u003c/div\u003e\u003c/li\u003e\u003cli\u003eThe RADIUS Access-Accept or Change-of-Authorization (CoA) assigns an ACL to that supplicant using RADIUS AVP (Attribute-Value pair) Filter-Id or NAS-Filter-Rule\u003c/li\u003e\u003c/ol\u003e\u003cdiv\u003e\u0026nbsp;\u003c/div\u003e\u003cp\u003eBelow is an example of one configuration. Note that \u201cmac based authentication always\u201d is optional The supplicant can authenticate with either EAPOL or MBA.\u003c/p\u003e\u003cpre\u003eswitch(config-if-et1)#show active\n \ninterface Ethernet5\n\u0026nbsp;\u0026nbsp;\u0026nbsp;switchport mode trunk\n\u0026nbsp;\u0026nbsp;\u0026nbsp;spanning-tree portfast edge\n dot1x pae authenticator\n\u0026nbsp;\u0026nbsp;\u0026nbsp;dot1x port-control auto\n \ndot1x system-auth-control\n\u003c/pre\u003e\u003cdiv\u003e\u0026nbsp;\u003c/div\u003e\u003cp\u003eIn this example port control is in \u201cauto\u201d mode, necessary for the condition to occur.\u003c/p\u003e\u003cpre\u003econfig)#show\u0026nbsp; dot1x\u0026nbsp; interface\u0026nbsp; ethernet 5 details\nDot1X Information for Ethernet5\n--------------------------------------------\nPort control: auto\nForced phone authorization: disabled\nEAPOL: enabled\nHost mode: multi-host\nMAC-based authentication: enabled\nMAC-based authentication host mode: Unconfigured\nMAC-based authentication always: enabled\nQuiet period: 60 seconds\nTX period: 5 seconds\nMaximum reauth requests: 2\nIgnore reauth timeout: No\nAuth failure VLAN: Unconfigured\nUnauthorized access VLAN egress: No\nUnauthorized native VLAN egress: No\nEAPOL authentication failure fallback: Unconfigured\nPort ErrDisabled by CoA: no\n \nDot1X Authenticator Client\n\u003c/pre\u003e\u003cdiv\u003e\u0026nbsp;\u003c/div\u003e\u003cp\u003e\u0026nbsp; Use a preconfigured ACL with which the RADIUS server returns in the \u003cb\u003eFilter-Id\u003c/b\u003e AVP\u003c/p\u003e\u003cpre\u003eswitch(config)#ip access-list EMPLOYEE-ACL\nswitch(config-ip-acl-EMPLOYEE-ACL)#10 permit ip 10.0.0.0/8 any\nswitch(config-ip-acl-EMPLOYEE-ACL)#20 deny ip any any\n\u003c/pre\u003e\u003cdiv\u003e\u0026nbsp;\u003c/div\u003e\u003cp\u003eAAA server will return the ACL name through \u003cb\u003eFilter-Id\u003c/b\u003e AVP through Access-Accept or CoA messages , in the above sample , Filter-Id AVP with EMPLOYEE-ACL will be received from the server.\u003c/p\u003e\u003cp\u003eTo verify the configured ACL, execute the following show command to identify the ACL applied to the interface:\u003c/p\u003e\u003cpre\u003eswitch(config)#show ip access-lists interface Ethernet5 summary\u0026nbsp;\nIP Access List EMPLOYEE-ACL\n\u0026nbsp;\u0026nbsp;\u0026nbsp;10 permit ip 10.0.0.0/8 any\n\u0026nbsp;\u0026nbsp;\u0026nbsp;20 deny ip any any\n \n\u0026nbsp;\u0026nbsp;\u0026nbsp;Total rules configured: 2\n\u0026nbsp;\u0026nbsp;\u0026nbsp;Configured on Ingress: Ethernet5\n\u0026nbsp;\u0026nbsp;\u0026nbsp;Active on Ingress: Ethernet5\u0026nbsp;\u003c/pre\u003e\u003cp\u003eIn addition to the prerequisite above to configure 802.1X in authenticator mode with ACL-based authorization, the supplicant(s) must be removed via the below command:\u003c/p\u003e\u003cpre\u003eswitch(config-dot1x)#clear dot1x host all\u003c/pre\u003e\u003c/pre\u003e"
}
],
"value": "In order to be vulnerable to any of the vulnerabilities, the following condition must be met under interface configuration mode:\n\n * 802.1X (dot1x in the CLI) must be configured with pae authenticator\u00a0\n\n\n * port-control must be set to auto mode\u00a0\n\n\n * A static or dynamic ACL must be configured.\u00a0\n\n\n * The RADIUS Access-Accept or Change-of-Authorization (CoA) assigns an ACL to that supplicant using RADIUS AVP (Attribute-Value pair) Filter-Id or NAS-Filter-Rule\n\u00a0\n\n\n\nBelow is an example of one configuration. Note that \u201cmac based authentication always\u201d is optional The supplicant can authenticate with either EAPOL or MBA.\n\n\n\nswitch(config-if-et1)#show active\n \ninterface Ethernet5\n\u00a0\u00a0\u00a0switchport mode trunk\n\u00a0\u00a0\u00a0spanning-tree portfast edge\n dot1x pae authenticator\n\u00a0\u00a0\u00a0dot1x port-control auto\n \ndot1x system-auth-control\n\n\n\u00a0\n\n\n\nIn this example port control is in \u201cauto\u201d mode, necessary for the condition to occur.\n\n\n\nconfig)#show\u00a0 dot1x\u00a0 interface\u00a0 ethernet 5 details\nDot1X Information for Ethernet5\n--------------------------------------------\nPort control: auto\nForced phone authorization: disabled\nEAPOL: enabled\nHost mode: multi-host\nMAC-based authentication: enabled\nMAC-based authentication host mode: Unconfigured\nMAC-based authentication always: enabled\nQuiet period: 60 seconds\nTX period: 5 seconds\nMaximum reauth requests: 2\nIgnore reauth timeout: No\nAuth failure VLAN: Unconfigured\nUnauthorized access VLAN egress: No\nUnauthorized native VLAN egress: No\nEAPOL authentication failure fallback: Unconfigured\nPort ErrDisabled by CoA: no\n \nDot1X Authenticator Client\n\n\n\u00a0\n\n\n\n\u00a0 Use a preconfigured ACL with which the RADIUS server returns in the Filter-Id AVP\n\n\n\nswitch(config)#ip access-list EMPLOYEE-ACL\nswitch(config-ip-acl-EMPLOYEE-ACL)#10 permit ip 10.0.0.0/8 any\nswitch(config-ip-acl-EMPLOYEE-ACL)#20 deny ip any any\n\n\n\u00a0\n\n\n\nAAA server will return the ACL name through Filter-Id AVP through Access-Accept or CoA messages , in the above sample , Filter-Id AVP with EMPLOYEE-ACL will be received from the server.\n\n\n\nTo verify the configured ACL, execute the following show command to identify the ACL applied to the interface:\n\n\n\nswitch(config)#show ip access-lists interface Ethernet5 summary\u00a0\nIP Access List EMPLOYEE-ACL\n\u00a0\u00a0\u00a010 permit ip 10.0.0.0/8 any\n\u00a0\u00a0\u00a020 deny ip any any\n \n\u00a0\u00a0\u00a0Total rules configured: 2\n\u00a0\u00a0\u00a0Configured on Ingress: Ethernet5\n\u00a0\u00a0\u00a0Active on Ingress: Ethernet5\u00a0\n\n\n\nIn addition to the prerequisite above to configure 802.1X in authenticator mode with ACL-based authorization, the supplicant(s) must be removed via the below command:\n\n\n\nswitch(config-dot1x)#clear dot1x host all"
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "Those issues were discovered internally by Arista, and the company is not aware of any malicious exploitation of these vulnerabilities in customer networks."
}
],
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"value": "\u003cpre\u003eA brief (milliseconds to seconds) traffic leak may occur when an authenticated supplicant is removed, either via the clear dot1x host all CLI command or due to a supplicant timeout. During this window, the supplicant\u0027s traffic may pass without ACL enforcement.\n\u003c/pre\u003e"
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"value": "A brief (milliseconds to seconds) traffic leak may occur when an authenticated supplicant is removed, either via the clear dot1x host all CLI command or due to a supplicant timeout. During this window, the supplicant\u0027s traffic may pass without ACL enforcement."
}
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"impacts": [
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"capecId": "CAPEC-131",
"descriptions": [
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"lang": "en",
"value": "CAPEC-131 Resource Leak Exposure"
}
]
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"metrics": [
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"attackVector": "ADJACENT_NETWORK",
"availabilityImpact": "NONE",
"baseScore": 2.6,
"baseSeverity": "LOW",
"confidentialityImpact": "NONE",
"integrityImpact": "LOW",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
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"Recovery": "NOT_DEFINED",
"Safety": "NOT_DEFINED",
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"baseScore": 2.1,
"baseSeverity": "LOW",
"exploitMaturity": "NOT_DEFINED",
"privilegesRequired": "LOW",
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"valueDensity": "NOT_DEFINED",
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"version": "4.0",
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"vulnConfidentialityImpact": "NONE",
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"cweId": "CWE-459",
"description": "CWE-459 Incomplete Cleanup",
"lang": "en",
"type": "CWE"
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"providerMetadata": {
"dateUpdated": "2026-09-14T22:11:53.107Z",
"orgId": "c8b34d1a-69ae-45c3-88fe-f3b3d44f39b7",
"shortName": "Arista"
},
"references": [
{
"url": "https://www.arista.com/en/support/advisories-notices/security-advisory/24706-security-advisory-0150"
}
],
"solutions": [
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"value": "\u003cpre\u003e\nCVE-2026-75943 has been fixed in the following releases:\n* 4.36.2F and later releases in the 4.36.x train.\n* 4.35.6M and later releases in the 4.35.x train.\n* 4.34.8M and later releases in the 4.34.x train.\n* 4.33.10M and later releases in the 4.33.x train.\n\u003c/pre\u003e"
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"value": "CVE-2026-75943 has been fixed in the following releases:\n* 4.36.2F and later releases in the 4.36.x train.\n* 4.35.6M and later releases in the 4.35.x train.\n* 4.34.8M and later releases in the 4.34.x train.\n* 4.33.10M and later releases in the 4.33.x train."
}
],
"source": {
"advisory": "Security Advisory 0150",
"defects": [
"BUG 1302705"
],
"discovery": "INTERNAL"
},
"title": "A brief (milliseconds to seconds) traffic leak may occur when an authenticated supplicant is removed, either via the clear dot1x host all CLI command or due to a supplicant timeout. During this window, the supplicant\u0027s traffic may pass without ACL enforcem",
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"value": "There is no workaround available for CVE-2026-75943."
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"datePublished": "2026-09-14T22:11:53.107Z",
"dateReserved": "2026-08-18T16:04:10.264Z",
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"nvd": "{\"cve\":{\"id\":\"CVE-2026-75943\",\"sourceIdentifier\":\"psirt@arista.com\",\"published\":\"2026-09-14T23:18:35.457\",\"lastModified\":\"2026-09-14T23:18:35.457\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"A brief (milliseconds to seconds) traffic leak may occur when an authenticated supplicant is removed, either via the clear dot1x host all CLI command or due to a supplicant timeout. During this window, the supplicant\u0027s traffic may pass without ACL enforcement.\"}],\"affected\":[{\"source\":\"psirt@arista.com\",\"affectedData\":[{\"vendor\":\"Arista Networks\",\"product\":\"EOS\",\"defaultStatus\":\"unaffected\",\"versions\":[{\"version\":\"4.36.0\",\"lessThanOrEqual\":\"4.36.1F\",\"versionType\":\"custom\",\"status\":\"affected\"},{\"version\":\"4.35.0\",\"lessThanOrEqual\":\"4.35.5M\",\"versionType\":\"custom\",\"status\":\"affected\"},{\"version\":\"4.34.0\",\"lessThanOrEqual\":\"4.34.7.1M\",\"versionType\":\"custom\",\"status\":\"affected\"},{\"version\":\"0.0.0\",\"lessThanOrEqual\":\"4.33.9M\",\"versionType\":\"custom\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV40\":[{\"source\":\"psirt@arista.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"4.0\",\"vectorString\":\"CVSS:4.0/AV:A/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/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\",\"baseScore\":2.1,\"baseSeverity\":\"LOW\",\"attackVector\":\"ADJACENT\",\"attackComplexity\":\"LOW\",\"attackRequirements\":\"PRESENT\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"vulnConfidentialityImpact\":\"NONE\",\"vulnIntegrityImpact\":\"LOW\",\"vulnAvailabilityImpact\":\"NONE\",\"subConfidentialityImpact\":\"NONE\",\"subIntegrityImpact\":\"NONE\",\"subAvailabilityImpact\":\"NONE\",\"exploitMaturity\":\"NOT_DEFINED\",\"confidentialityRequirement\":\"NOT_DEFINED\",\"integrityRequirement\":\"NOT_DEFINED\",\"availabilityRequirement\":\"NOT_DEFINED\",\"modifiedAttackVector\":\"NOT_DEFINED\",\"modifiedAttackComplexity\":\"NOT_DEFINED\",\"modifiedAttackRequirements\":\"NOT_DEFINED\",\"modifiedPrivilegesRequired\":\"NOT_DEFINED\",\"modifiedUserInteraction\":\"NOT_DEFINED\",\"modifiedVulnConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedVulnIntegrityImpact\":\"NOT_DEFINED\",\"modifiedVulnAvailabilityImpact\":\"NOT_DEFINED\",\"modifiedSubConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedSubIntegrityImpact\":\"NOT_DEFINED\",\"modifiedSubAvailabilityImpact\":\"NOT_DEFINED\",\"Safety\":\"NOT_DEFINED\",\"Automatable\":\"NOT_DEFINED\",\"Recovery\":\"NOT_DEFINED\",\"valueDensity\":\"NOT_DEFINED\",\"vulnerabilityResponseEffort\":\"NOT_DEFINED\",\"providerUrgency\":\"NOT_DEFINED\"}}],\"cvssMetricV31\":[{\"source\":\"psirt@arista.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:A/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N\",\"baseScore\":2.6,\"baseSeverity\":\"LOW\",\"attackVector\":\"ADJACENT_NETWORK\",\"attackComplexity\":\"HIGH\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"LOW\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":1.2,\"impactScore\":1.4}]},\"weaknesses\":[{\"source\":\"psirt@arista.com\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-459\"}]}],\"references\":[{\"url\":\"https://www.arista.com/en/support/advisories-notices/security-advisory/24706-security-advisory-0150\",\"source\":\"psirt@arista.com\"}]}}"
}
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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