CVE-2026-73440Security Advisory 0178

Description

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.

Timeline

Scores

EPSS (exploitation in 30 days)

0.27% · top 81% of all CVEs (13 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: Low 2.3.

Affected products

• Arista Networks · EOS

  • affected 4.36.0F – ≤ 4.36.2F
  • affected 4.35.0F – ≤ 4.35.6M
  • affected 4.34.0F – ≤ 4.34.8M
  • affected 4.33.0F – ≤ 4.33.10M
  • affected 1.0.0 – < 4.33.0F

What to do

Solution: 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-server snmp-server user alice group_alice v3 localized f5717f2cdde9bb946d00 auth sha256 key 7 005D110205085E520B754E1B591C504542585F557D2F217064607A10034752035500080755575640440F5C00505053515F08525208035C1605525E0A040E781F4D CVE-2026-73440 has been fixed in the following releases: * 4.36.3M and later releases in the 4.36.x train * 4.35.7M and later releases in the 4.35.x train * 4.34.9M and later releases in the 4.34.x train * 4.33.11M and later releases in the 4.33.x train

Workaround: CVE-2026-73440 can be remediated using the hotfix detailed below. This hotfix is strictly applicable to the listed releases. All non-listed versions must be upgraded to a fixed release as specified above.   * 4.36.2F * 4.35.6M * 4.34.8M * 4.33.10M Post hotfix installation, users are required to execute the syntax conversion command to fix the malformed keys. Note: Installing/uninstalling the SWIX will cause the ConfigAgent process to restart. Version: 1.0 URL: SecurityAdvisory178_CVE-2026-73440_Hotfix.swix https://www.arista.com/support/advisories-notices/sa-download/ SWIX hash: 8a11df104d6ada97f0d63ca87a6a03071524038af1f8cd4a0bbcba490ab80245c7b2cfb86be81c5e6773e05801f3df098120f6053b130938230c79193386fe74   For instructions on installation and verification of the hotfix patch, refer to the “ managing eos extensions https://www.arista.com/en/um-eos/eos-managing-eos-extensions ” section in the EOS User Manual. Ensure that the patch is made persistent across reboots by running the command ‘copy installed-extensions boot-extensions’.

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• EUVD EUVD-2026-80591 (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-73440](https://cveledger.app/badge/CVE-2026-73440.svg)](https://cveledger.app/cve/CVE-2026-73440)

Record last updated 8 Nov 2026, 10:31 UTC.