CVE-2026-73437 (CVSS 9.6)

Description

On affected platforms running Arista EOS with Dynamic Host Configuration Protocol (DHCP) relay configured, an unauthenticated attacker with network access could send a crafted DHCP reply packet from an IP address that is not configured as a helper address, and the relay agent would forward it to clients without validating the source. This could allow the attacker to supply clients with malicious network configuration parameters, potentially resulting in traffic interception or denial of service for affected clients.

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CVSS v3.1 Score

9.6

CRITICAL

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

EPSS — Exploit Prediction

0.0020

Probability of exploitation

0.10%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-345 CWE-345

References

Other References

https://www.arista.com/en/support/advisories-notices/security-advisory/24712-security-advisory-0156

Frequently Asked Questions

What is CVE-2026-73437? +

On affected platforms running Arista EOS with Dynamic Host Configuration Protocol (DHCP) relay configured, an unauthenticated attacker with network access could send a crafted DHCP reply packet from an IP address that is not configured as a helper address, and the relay agent would forward it to clients without validating the source. This could allow the attacker to supply clients with malicious network configuration parameters, potentially resulting in traffic interception or denial of service for affected clients. It has a CVSS v3.1 base score of 9.6 (CRITICAL).

How severe is CVE-2026-73437? +

CVE-2026-73437 has a CVSS v3.1 score of 9.6 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0020, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-73437? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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