Is CVE-2026-120978 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-120978 being exploited in the wild.

How severe is CVE-2026-120978?

Medium severity, with a CVSS score of 6.5, published 10 November 2026.

Which products and versions are affected?

Arista Eos 4.36.2F and below in 4.36.x; 4.35.6M and below in 4.35.x; 4.34.8M and below in 4.34.x; 4.33.10M and below in 4.33.x; all 4.32.x releases; all End of Support releases.

How is CVE-2026-120978 attacked?

It is attacked over the network.

Am I affected by CVE-2026-120978?

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.

CVE-2026-120978: Arista EOS denial of service in BGP-LS

CVE-2026-120978 · Severity: medium · CVSS 6.5 · Published 2026-11-10

Arista EOS network operating system running Border Gateway Protocol with Link State (BGP-LS) in Dynamic Path Selection consumer mode contains a flaw that allows an authenticated attacker to crash the BGP routing service with a crafted message. This causes the routing process to restart unexpectedly, disrupting network traffic and potentially creating an outage in production networks.

Technologies: Arista Eos. Vendors: Arista.

Quick answers

Is CVE-2026-120978 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-120978 being exploited in the wild.
How severe is CVE-2026-120978?: Medium severity, with a CVSS score of 6.5, published 10 November 2026.
Which products and versions are affected?: Arista Eos 4.36.2F and below in 4.36.x; 4.35.6M and below in 4.35.x; 4.34.8M and below in 4.34.x; 4.33.10M and below in 4.33.x; all 4.32.x releases; all End of Support releases.
Is there a fix for CVE-2026-120978?: Yes: fixed in 4.37.0F and later (4.37.x); 4.36.3M and later (4.36.x); 4.35.7M and later (4.35.x); 4.34.9M and later (4.34.x); 4.33.11M and later (4.33.x). Until then: No configuration-level mitigations are available; software upgrade is required to fully resolve the issue. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-120978 attacked?: It is attacked over the network.
Am I affected by CVE-2026-120978?: 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.

How to fix

Fixed in: 4.37.0F and later (4.37.x); 4.36.3M and later (4.36.x); 4.35.7M and later (4.35.x); 4.34.9M and later (4.34.x); 4.33.11M and later (4.33.x)

No configuration-level mitigations are available; software upgrade is required to fully resolve the issue.

Technical details

A null pointer dereference or reachable assertion in the BGP-LS message handling code allows an authenticated BGP peer to trigger a BGP agent restart. The vulnerability requires an established BGP-LS peer session with the device configured as a Dynamic Path Selection consumer; an attacker must have network access and valid BGP credentials to exploit it. The attack results in denial of service to the BGP service on the affected platform.

Affected products

Arista EOS 4.36.2F and below in 4.36.x; 4.35.6M and below in 4.35.x; 4.34.8M and below in 4.34.x; 4.33.10M and below in 4.33.x; all 4.32.x releases; all End of Support releases

Timeline

2026-11-10: disclosed

References

https://www.arista.com/en/support/advisories-notices/security-advisory/25033-security-advisory-0211

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