On affected platforms running Arista EOS with both 802.1X port authentication and the RADIUS proxy feature configured with dynamic authorization, a low-privileged attacker on an adjacent network segment who induces a RADIUS packet through a configured RADI

published 2026-09-14 last mo. modified 2026-09-16 last mo. also EUVD-2026-78170

cvss: 5.9; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 15%
public exploits: 0; none known

On affected platforms running Arista EOS with both 802.1X port authentication and the RADIUS proxy feature configured with dynamic authorization, a low-privileged attacker on an adjacent network segment who induces a RADIUS packet through a configured RADIUS proxy client can prevent RADIUS dynamic authorization messages, including Change-of-Authorization (CoA) and Disconnect-Requests as defined in RFC 5176, from being applied to locally authenticated 802.1X sessions. This allows an endpoint session that a RADIUS server or network access control system has ordered disconnected to remain authorized on the network. Both 802.1X port authentication with dynamic authorization and RADIUS proxy with dynamic authorization must be explicitly configured for a deployment to be exposed to this issue. This issue was discovered internally by Arista, and the company is not aware of any malicious exploitation of this vulnerability in customer networks.

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CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: last mo. (2026-09-15)

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 15% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by	version	score	vector
CNA	3.1	5.9	CVSS:3.1/AV:A/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:L
CNA	4.0	5.9	CVSS:4.0/AV:A/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:L/SA:L
CNA	4.0	5.9	CVSS:4.0/AV:A/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:L/SA:L/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 products

Arista Networks EOS

Classification

Weakness

CWE-290 Authentication Bypass by Spoofing

References

arista.com /en/support/advisories-notices/security-advisory/24705-security-advisory-0149

Sources

CVE List CVE-2026-73449
NVD CVE-2026-73449

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