# CVE-2026-73453: Arista EOS P4Runtime arbitrary code execution

Source: https://junglewise.ai/threats/cve-2026-73453-arista-eos-p4runtime-arbitrary-code-execution  
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-2026-73453 · Severity: critical · CVSS 10 · Published 2026-09-16

Arista EOS network switches support an optional P4Runtime protocol for programmatic packet processing control. An unauthenticated attacker can craft a malicious packet to achieve arbitrary code execution and gain full administrative control over an affected switch, but only if P4Runtime is explicitly enabled (disabled by default). Arista has not observed active exploitation in customer networks.

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

## Quick answers

**Is CVE-2026-73453 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-73453 being exploited in the wild.

**How severe is CVE-2026-73453?** Critical severity, with a CVSS score of 10, published 16 September 2026.

**Which products and versions are affected?** Arista Eos 4.36.1F and earlier 4.36.x, 4.35.5M and earlier 4.35.x, 4.34.7M and earlier 4.34.x, all 4.33.x, all 4.32.x, all 4.31.x, all 4.30.x, 4.29.2F and later in 4.29.x.

**Is there a fix for CVE-2026-73453?** 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-2026-73453 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-73453?** 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

This vulnerability is a code injection flaw (CWE-94) in the P4Runtime session initialization logic. An unauthenticated network-accessible attacker can exploit this by sending a specially crafted packet during P4Runtime session setup to achieve remote code execution with administrative privileges. The vulnerability affects Arista EOS versions through 4.36.1F and earlier in multiple release trains when P4Runtime is configured in non-TLS mode, TLS mode without trusted certificates, or mTLS mode without proper gNSI authorization controls. No user interaction is required; the attack occurs at the protocol level during session negotiation. Patches are available through updated EOS versions beyond the affected release trains.

## Affected products

- Arista EOS 4.36.1F and earlier 4.36.x, 4.35.5M and earlier 4.35.x, 4.34.7M and earlier 4.34.x, all 4.33.x, all 4.32.x, all 4.31.x, all 4.30.x, 4.29.2F and later in 4.29.x

## Timeline

- 2026-09-16: disclosed
- 2026-09-09: advisory

## References

- [https://www.arista.com/en/support/advisories-notices/security-advisory/24730-security-advisory-0174](https://www.arista.com/en/support/advisories-notices/security-advisory/24730-security-advisory-0174)

## 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)