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Arista EOS EUVDEUVD-2026-81000

| CVE-2026-73442 LOW
Insertion of Sensitive Information into Log File (CWE-532)
2026-09-16 Arista GHSA-2p66-p32j-x932
2.1
CVSS 4.0 · Vendor: Arista
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Obtain privileged log-read or syslog access
  2. Exploit
    Open EOS agent trace logs
  3. Execution
    Read cleartext VRRP peer credentials
  4. Impact
    Reuse credentials to spoof/manipulate VRRP

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A09:2025 - Security Logging & Alerting Failures
ASVS 5.0
V16 - Security Logging and Error Handling Log data sanitization
Exploitation Conditions

Requires that VRRP is enabled on the affected Arista EOS switch (the credentials only exist when VRRP with authentication is configured), AND that the attacker holds sufficient privileges to view EOS agent trace logs on the switch OR has access to a system receiving forwarded/syslog output of those logs. Limiting factors: exploitation needs an authenticated, privileged management context (PR:L/PR:H) - it is not remotely reachable by an unauthenticated attacker; impact is confined to disclosure of the peer VRRP shared secret (confidentiality only, no integrity/availability effect). The notable feature that raises the bug above pure log-hygiene is that it does NOT require access to the VRRP network segment.

Impact

This is a genuinely low-priority issue, and the signals agree rather than conflict. The vendor CVSS 4.0 score is 2.1 (AV:A/AC:H/PR:L, VC:L only), reflecting a narrow credential-disclosure problem: VRRP peer authentication credentials are written to agent trace logs in cleartext (CWE-532). Exploitation status is no public exploit identified at time of analysis - there is no CISA KEV listing, no POC, and no EPSS score in the provided data, all consistent with a low-interest logging bug. The one nuance worth flagging is the vendor's choice of AV:A (adjacent) with AC:H: the description frames this as reading local agent trace logs on the switch (or logs forwarded to a syslog collector), which reads more like a local/authenticated disclosure than an adjacent-network attack - the AV:A likely models the management-plane access needed, but AV:L is defensible. The real value of the flaw to an attacker is that it leaks peer VRRP credentials WITHOUT the attacker needing access to the network segment where VRRP runs, converting a log-read privilege into a credential the attacker otherwise could not obtain. Impact is limited to confidentiality of a single protocol's shared secret (VC:L, no integrity or availability impact).

Exploit ScenarioDerived

An authenticated operator (or an attacker who has compromised a low-privilege management account or a downstream syslog/log-collection server) reads the Arista EOS agent trace logs and finds the peer device's VRRP authentication credentials in cleartext. With those credentials, they could later spoof VRRP advertisements to influence gateway election, despite never having had direct access to the VRRP network segment. No public exploit code is required - the disclosure is passive log-reading.

Monitor Track and reassess. Why: LOW severity (CVSS 0.1-3.9).
No patch listed yet 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Sep 16, 2026

Cleartext disclosure of peer VRRP authentication credentials in Arista EOS log output allows an authenticated, privileged user - or anyone able to read a system receiving forwarded agent trace logs - to recover the shared secret that authenticates VRRP advertisements, without needing any presence on the VRRP network segment itself. The defect applies to EOS platforms configured with authenticated VRRP; exploitation requires high-privilege access to the switch's agent trace logs or to a downstream log collector, and the resulting impact is confidentiality-only (CVSS 4.0 base 2.1; our independent assessment rates it CVSS 3.1 AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N, i.e. PR:H and C:L). No public exploit code and no confirmed active exploitation were identified at time of analysis; this is a low-priority log-hygiene issue whose only notable edge over routine secret-in-log bugs is that the leak escapes the on-link boundary normally assumed for VRRP secrets.

RemediationAI

No vendor-released patch version is identified in the available data; treat Arista Security Advisory 0157 (https://www.arista.com/en/support/advisories-notices/security-advisory/24713-security-advisory-0157) as the authoritative source for the fixed EOS releases and upgrade all VRRP-authenticating switches as soon as a maintenance window permits. Because the leaked value is a shared secret, patching alone is insufficient - rotate the VRRP authentication strings on every affected virtual router pair after upgrading, coordinating both peers so failover is not disturbed. In the interim, compensating controls are: restrict access to EOS agent trace output and logging commands to the smallest possible set of privileged roles via EOS role-based access control (trade-off: reduces operational troubleshooting ability for the network team); exclude VRRP-related agent trace facilities from any syslog or log-forwarding destination that is not fully trusted, or stop forwarding agent trace verbosity altogether (trade-off: degrades diagnostics for VRRP and adjacent agent behaviour); and harden downstream log collectors with access controls and at-rest protection, since any historical logs already containing the credential remain sensitive even post-patch. Disabling VRRP authentication altogether removes the leak but materially weakens protection against rogue VRRP speakers on the segment and should only be considered where the segment is strictly controlled and monitored; switching to a mechanism that does not rely on a replayable cleartext shared secret is preferable if the platform supports it.

Affected VersionsENISA

EOS 4.34.0 ≤4.34.7M
EOS 4.35.0 ≤4.35.5M
EOS 4.36.0 ≤4.36.1F
EOS 4.33.0 ≤4.33.9M

Affected Packages

euvd eos no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

VRRP (Virtual Router Redundancy Protocol) peers can authenticate their advertisements so that a rogue speaker cannot seize the virtual router's IP. Where authentication is configured on EOS, the peer's authentication string is handled by the routing/VRRP agent and, per this advisory, is written into agent trace logs rather than being masked - the root-cause class is CWE-532, Insertion of Sensitive Information into Log File. Because EOS agent trace output can be consumed locally via privileged show/trace commands and is also commonly streamed off-box via syslog or other log-forwarding transports, the credential can leave the device through the logging plane instead of the data plane, which is what removes the usual requirement of access to the VRRP segment. The affected-product CPE cpe:2.3:a:arista_networks:eos:*:*:*:*:*:*:*:* carries a wildcard version field, so the advisory (Arista Security Advisory 0157) rather than the CPE must be consulted to determine which EOS trains and releases are in scope. Note the divergence between the CVSS 4.0 vector, which frames the attack as adjacent-network with low privileges (AV:A/AC:H/PR:L) and low confidentiality across both vulnerable and subsequent systems, and our assessment, which treats the realistic path as local high-privilege log access with only vulnerable-system confidentiality affected (AV:L/PR:H, S:U/C:L).

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Severity by source

Vendor (Arista) PRIMARY 2.1 LOW
CVSS:4.0/AV:A/AC:H/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N
vuln.today AI 2.3 LOW

Reading on-switch agent trace logs requires privileged management access (PR:H, AV:L); impact is limited to disclosure of the VRRP peer secret (C:L), with no integrity or availability effect.

3.1 AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N
4.0 AV:L/AC:L/AT:N/PR:H/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

Primary rating from Vendor (Arista).

CVSS VectorVendor: Arista

Attack Vector
Adjacent
Attack Complexity
High
Attack Requirements
None
Privileges Required
Low
User Interaction
None
Vulnerable system: Confidentiality
Low
Vulnerable system: Integrity
None
Vulnerable system: Availability
None
Subsequent system: Confidentiality
Low
Subsequent system: Integrity
None
Subsequent system: Availability
None

Lifecycle Timeline

1
CVSS changed
Sep 16, 2026 - 19:22 NVD
3.0 (LOW) 2.1 (LOW)

DescriptionCVE.org

On affected platforms running Arista EOS with VRRP enabled, the peer device VRRP authentication credentials are logged in cleartext on the switch, allowing an authenticated user with sufficient privileges to view agent trace logs (or a system receiving forwarded log output) to obtain the peer device VRRP authentication credentials without having access to the network segment on which VRRP is running.

Threat Intelligence Overview

EPSS Score
0.2%
Top 89% exploitable
Prevalence
Medium
Arista EOS common in enterprise/data-center switching, scoped to VRRP-enabled configs
Data Quality
4 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity LOW
CISA KEV No
Public POC No
EPSS 0.2%
Patch available No
Active threat No
Deciding rule
LOW severity (CVSS 0.1-3.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Defer
Exploitation· derived
None
System Exposure· derived
Controlled
Automatable· derived
No
Human Impact· derived
Low

Priority Score

10
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +10
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

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