Arista EOS: BGP peer can churn VPLS pseudowire routes toward other legitimate peers

CVSS 6.0CVE-2026-120981Firmware, BMC & network fabriccurated

Impact

An established BGP peer can tamper with the route advertisements of VPLS pseudowires, causing the routes established with other legitimate BGP peers to churn. The result is instability in the VPLS service across peers, not just on the attacker's own session. This shares an advisory with CVE-2026-120980 but is a separate flaw: route manipulation rather than an agent crash. Only switches with VPLS-BGP enabled are affected.

Who can reach it

An attacker who already has an established BGP session with the PE router. Only switches with VPLS-BGP enabled are affected.

What to do

Upgrade EOS to a fixed release from Arista Security Advisory 0214. The record does not list fixed versions. Plan each switch upgrade around fabric redundancy, and restrict BGP peering to trusted, authenticated neighbors in the meantime.

References

https://nvd.nist.gov/vuln/detail/CVE-2026-120981 https://www.arista.com/en/support/advisories-notices/security-advisory/25036-security-advisory-0214

This entry is curated: imported from vendor advisories with machine assistance, not yet individually verified. Confirm against your vendor's advisory before acting, and report anything wrong.