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PatchSiren cyber security CVE debrief

CVE-2026-7473 Arista Networks CVE debrief

CVE-2026-7473 is a vulnerability in Arista EOS where a tunnel decapsulation configuration is present, allowing an attacker to incorrectly decapsulate and forward other unexpected tunneled packets with a destination IP matching its configured decapsulation IP. This occurs because the switch does not verify the tunnel protocol type, potentially leading to the unexpected processing of non-configured tunnel traffic. The vulnerability has a CVSS score of 6.9 and is considered Medium severity. It has been reported as being exploited in the wild.

Vendor
Arista Networks
Product
EOS
CVSS
MEDIUM 6.9
CISA KEV
Listed
Original CVE published
2026-06-09
Original CVE updated
2026-06-09
Advisory published
2026-06-09
Advisory updated
2026-06-09

Who should care

Administrators and users of Arista EOS, particularly those with tunnel decapsulation configurations such as VXLAN, decap-groups, or GRE tunnel interfaces.

Technical summary

The vulnerability is caused by the lack of verification of the tunnel protocol type in Arista EOS, allowing for the incorrect decapsulation and forwarding of tunneled packets. This code affects multiple Arista products.

Defensive priority

High

Recommended defensive actions

  • Apply patches or updates provided by Arista to address the vulnerability.
  • Review and update tunnel decapsulation configurations to ensure they are properly configured and secured.
  • Monitor network traffic for suspicious activity related to tunnel decapsulation.

Evidence notes

CVE-2026-7473 has been reported by CISA as being known to be exploited in the wild. Arista has provided security advisories and mitigation guidance.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-7473 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-7473

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-7473 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-7473

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

  • CISA Known Exploited Vulnerabilities catalog

    Publisher, destination, and source semantics verified

    URL: https://www.cisa.gov/known-exploited-vulnerabilities-catalog

    Cybersecurity and Infrastructure Security Agency - Official CISA catalog of vulnerabilities known to be exploited in the wild.

Supplemental references

  • Source reference

    Unverified legacy reference

    URL: https://www.arista.com/en/support/advisories-notices/security-advisory/22872-security-advisory-0137

    [email protected] - Broken Link

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://www.arista.com/en/support/advisories-notices/security-advisory/24005-security-advisory-0137

    134c704f-9b21-4f2e-91b3-4a467353bcc0 - Vendor Advisory, Mitigation

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.