Arista EOS: Sensitive authentication data in diagnostic data during SSU
Summary
On Arista EOS switches using IEEE 802.1X with MACsec and dynamically derived keys, sensitive authentication information may be written to diagnostic data during a Smart Switch Upgrade (SSU). An attacker with administrative access to the device who obtains this diagnostic data could recover authentication information and potentially compromise the confidentiality and integrity of MACsec-protected traffic on the affected link. The exposure exists only during and after an SSU reload while an active 802.1X session used for MACsec is present.
Affected
- Arista EOS 4.22.0F to before 4.32.0F (unconfirmed, verify with the vendor advisory)
- Arista EOS 4.32.0F to before 4.33.0F (unconfirmed)
- Arista EOS 4.33.0F to 4.33.9M (unconfirmed)
- Arista EOS 4.34.0F to 4.34.8M (unconfirmed)
- Arista EOS 4.35.0F to 4.35.6M (unconfirmed)
- Arista EOS 4.36.0F to 4.36.2F (unconfirmed)
- Configuration required: 802.1X with MACsec profile using 'key source dot1x'
Fixed in
Unknown. No verified list of fixed versions was found; check the Arista advisory 25038-security-advisory-0216.
Workaround
Unknown. No vendor workaround was found in the sources.
Exploitation
- No known exploitation in the wild.
- No public proof-of-concept known.
- Exploitation requires administrative (high-privilege) access to the device.
Our recommendation
- Check whether any Arista EOS devices are in use and whether they use 802.1X with dynamic MACsec keys.
- Open the Arista advisory 25038-security-advisory-0216 to confirm affected and fixed versions.
- Restrict administrative access to the switches.
- Treat diagnostic and support bundles from affected switches as sensitive, do not share them, and delete them after use.
- Review SSU timing on affected links and plan patching once fixed versions are confirmed.
- Priority: low to medium for most SMEs, higher where MACsec is used for compliance or link protection.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Arista Security Advisory 0216 (25038) www.arista.com
- CVE and CNA data (threatint mirror) cve.threatint.com
- Affected version ranges (Strix) www.strix.ai
- VulDB entry vuldb.com
- Arista MACsec documentation www.arista.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 11 Nov 2026, 07:27.
Original description (NVD)
On affected platforms running Arista EOS with IEEE 802.1X authentication and MACsec using dynamically derived keys, sensitive authentication information may be recorded in diagnostic data during a Smart Switch Upgrade (SSU). An attacker with administrative access on the device who obtains the affected diagnostic data could recover sensitive authentication information. This could potentially compromise the confidentiality and integrity of traffic protected by MACsec on the affected link. The vulnerability is only exposed during and after an SSU reload where an active 802.1X session used for MACsec is present.
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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