# CVE-2026-73462: Arista EOS IGMP snooping denial of service via malformed packets

Source: https://junglewise.ai/threats/cve-2026-73462-arista-eos-igmp-snooping-denial-of-service-via-malformed-packets  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-16. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-73462 · Severity: medium · CVSS 6.5 · Published 2026-09-16

Arista EOS network switches are vulnerable to a denial-of-service attack via malformed IGMP (multicast management) packets. An attacker on the same network can crash the IGMP snooping service, causing multicast traffic to flood all network ports until the service restarts. Repeated attacks could sustain prolonged disruption of multicast traffic management.

Technologies: [Arista Eos](https://junglewise.ai/threats/technologies/eos). Vendors: [Arista](https://junglewise.ai/threats/vendors/arista).

## Quick answers

**Is CVE-2026-73462 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-73462 being exploited in the wild.

**How severe is CVE-2026-73462?** Medium severity, with a CVSS score of 6.5, published 16 September 2026.

**Which products and versions are affected?** Arista Eos 4.36.1F and earlier in 4.36.x, 4.35.5M and earlier in 4.35.x, 4.34.7.1M and earlier in 4.34.x, 4.33.8M and earlier in 4.33.x, and all prior releases.

**Is there a fix for CVE-2026-73462?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-73462 attacked?** It is attacked from the adjacent network, in a network appliance.

**Am I affected by CVE-2026-73462?** Check whether you run Arista Eos at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

An out-of-bounds read (CWE-125) in the IGMP snooping agent of Arista EOS allows a network-adjacent, unauthenticated attacker to send specially crafted IGMP packets on an affected VLAN. The malformed packets trigger a crash of the IGMP snooping service (signal 11), temporarily disabling multicast traffic management and causing multicast packets to be flooded to all VLAN ports until the service recovers. IGMP snooping is enabled by default on all VLANs; no special configuration is required for exploitation. Arista has released fixed versions in all supported release trains: 4.36.2F+, 4.35.6M+, 4.34.8M+, and 4.33.9M+. No workaround or hotfix is available; upgrade is the only mitigation.

## Affected products

- Arista EOS 4.36.1F and earlier in 4.36.x, 4.35.5M and earlier in 4.35.x, 4.34.7.1M and earlier in 4.34.x, 4.33.8M and earlier in 4.33.x, and all prior releases

## Timeline

- 2026-09-16: disclosed
- 2026-09-09: advisory: Arista Security Advisory 0159 published

## References

- [https://www.arista.com/en/support/advisories-notices/security-advisory/24715-security-advisory-0159](https://www.arista.com/en/support/advisories-notices/security-advisory/24715-security-advisory-0159)

## Related threats

- [Arista EOS path traversal in eAPI service](https://junglewise.ai/threats/cve-2026-121371-on-affected-eos-versions-with-the-eapi-service-enabled-a)
- [Arista EOS denial of service in PTP](https://junglewise.ai/threats/cve-2026-121370-on-affected-platforms-running-arista-eos-with-precision-time)
- [Arista EOS denial of service via resource exhaustion](https://junglewise.ai/threats/cve-2026-121369-on-affected-platforms-running-arista-eos-under-specific-link)
- [Arista EOS BFD authentication out-of-bounds write](https://junglewise.ai/threats/cve-2026-121368-on-affected-platforms-running-arista-eos-with-bidirectional)
- [Arista EOS RIPv2 silent enablement on management interfaces](https://junglewise.ai/threats/cve-2026-121367-on-affected-arista-eos-platforms-with-routing-information)