What is CVE-2026-73440?

CVE-2026-73440 is Security Advisory 0178. The supplied enrichment data classifies it as Unclassified mapped to CWE-212 CWE-212.

Which versions are affected?

Affected product and version evidence is listed in the product table above. Current public advisories should be checked for exact version scope before patch targeting is finalized.

Is there active exploitation?

Active exploitation is not confirmed from current sources for CVE-2026-73440. If exploitation is not confirmed from current sources, teams should document that status and continue monitoring KEV, vendor, and telemetry updates.

No. CVE-2026-73440 is not listed in CISA KEV in the supplied enrichment data. KEV status should be monitored because it can change after initial disclosure or after exploitation becomes publicly confirmed.

Is there a public exploit?

A public PoC is not confirmed from current sources for CVE-2026-73440. Public exploit or PoC availability should raise triage priority, especially for exposed or business-critical systems.

How can defenders detect it?

Start with web/proxy/WAF logs, application logs, network IDS/IPS where available. Look for vulnerability-class behavior, product errors, suspicious authentication events, exploit probes, and abnormal process activity based only on evidence that applies to the affected product.

How should teams prioritize it?

Prioritize CVE-2026-73440 using CVSS 4.2, EPSS 0%, KEV status, public PoC status, and asset exposure. Internet-facing, privileged, or business-critical deployments should be handled first.

Are workarounds available?

Workarounds are not confirmed from current sources. Fixed-version evidence is listed in the mitigation section above.

Which threat actors are linked publicly?

No public threat actor linkage is confirmed from current sources. Do not attribute exploitation to a threat actor unless the source evidence explicitly supports that linkage.

What should be done in the next 24 hours?

Identify exposed assets running affected vendor/product/version combinations. Prioritize based on EPSS, PoC availability, and external exposure. Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class. Open remediation tickets with affected assets, owners, evidence status, and detection coverage so decisions are traceable.

medium

CVE-2026-73440

CVE-2026-73440 — Security Advisory 0178

On affected platforms running Arista EOS with Simple Network Management Protocol (SNMP) configured, SNMPv3 local or remote user credentials may be exposed as a one-way hashed, localized key value within the device's running and sanitized configurations. An authenticated user who gains access to this sensitive information could leverage it to perform unauthorized read operations on SNMP tables or to send fraudulent trap notifications to the Network Management System (NMS). This issue was discovered internally by Arista, and the company is not aware of any malicious exploitation of this vulnerability in customer networks.

Published Sep 16, 2026Updated Sep 16, 2026Sources: NVD, Arista Networks (CNA), GitHub, SOCRadar CTI

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Unreported

no source claims exploitation

EPSS

ahead of 0% of scored CVEs

Affects

Arista Networks

5 products listed

CVSS base

4.2

medium · 2 sources

Remediation

The vendor's own words where we have them.

The recommended resolution is to upgrade to a remediated software version at your earliest convenience. Arista recommends customers move to the latest version of each release that contains all the fixes listed below. Following the system upgrade, users are required to execute the syntax conversion command specified below to adopt the updated, encrypted SNMPv3 CLI format: switch# configure convert new-syntax The updated encrypted SNMPv3 CLI configuration follows this structure, incorporating the newly introduced "key <algo> <encrypted_text>" syntax: switch# show running-config | grep snmp-serv…

First 24 hours

Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.

Identify exposed assets running affected vendor/product/version combinations.
Prioritize based on EPSS, PoC availability, and external exposure.
Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.

Affected scope

Vendor, product and version as the advisories word them.

Vendor	Product	Versions	Status
Arista Networks	EOS	4.36.0F to <= 4.36.1F	Vulnerable
Arista Networks	EOS	4.35.0F to <= 4.35.5M	Vulnerable
Arista Networks	EOS	4.34.0F to <= 4.34.7.1M	Vulnerable
Arista Networks	EOS	4.33.0F to <= 4.33.9M	Vulnerable
Arista Networks	EOS	1.0.0 to < 4.33.0F	Vulnerable

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Availability

None

Confidentiality

Low

Integrity

Low

Scope

Unchanged

Attack Complexity

High

Attack Vector

Network

Privileges Req

Low

User Interaction

None

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Source
4.2	CVSS 3.1	medium	1.6	2.5	Arista Networks (CNA)
2.3	CVSS 4.0	low	—	—	Arista Networks (CNA)

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N

What this weakness leads to

MITRE's own consequences and mitigations for the weakness class — the authority's wording, not guidance derived from the CVSS vector.

MITRE

CWE-212 · Improper Removal of Sensitive Information Before Storage or Transfer

Read Files or Directories
Read Application Data

Mitigation: Clearly specify which information should be regarded as private or sensitive, and require that the product offers functionality that allows the user to cleanse the sensitive information from the resource before it is published or exported to other parties.

Weakness & attack patterns

CWE-212

Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.

CAPEC-168 · Windows ::DATA Alternate Data Stream

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

Prioritize edge telemetry for network-reachable EOS.

web/proxy/WAF logsapplication logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.

2026
Added · CVSS 3.1 4.2 (AV:N)
Sep 16, 2026 · NVD
Initial · CVE published
Sep 16, 2026 · NVD
CVE published by MITRE.
Sep 16, 2026 · SOCRadar CTI

References

1 on the record

www.arista.com/en/support/advisories-notices/security-advisory/24734-security-advisory-0178
Vendor Advisory, Mitre

Elsewhere on this site

Arista Networksevery CVE for this vendor
Unclassifiedsame class
CWE-212other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record1

What should defenders know first?

CVE-2026-73440 is Security Advisory 0178, a medium vulnerability affecting EOS from Arista Networks. The current evidence does not list it in CISA KEV, and the exploit status is: Active exploitation is not confirmed from current sources for CVE-2026-73440. Public exploit evidence is: A public PoC is not confirmed from current sources for CVE-2026-73440. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 4.2 describes technical severity, while EPSS 0% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.