# -\> BGP handling bug causes widespread internet routing instability

DevFeed: [-\> BGP handling bug causes widespread internet routing instability](<https://devfeed.tech/articles/bgp-handling-bug-causes-widespread-internet-routing-instability-36146.md>)

Original publisher: [Read original article](<https://blog.benjojo.co.uk/post/bgp-attr-40-junos-arista-session-reset-incident>)

Published: 2025-05-28T13:06:04Z

Content type: article

Language: en

Sources: [BGPexpert](<https://devfeed.tech/sources/bgpexpert.md>)

Topics: [BGP](<https://devfeed.tech/topics/bgp.md>), [Routing (disambiguation)](<https://devfeed.tech/topics/routing.md>), [incident](<https://devfeed.tech/topics/incident.md>), [networking](<https://devfeed.tech/topics/networking.md>), [Internet Traffic](<https://devfeed.tech/topics/internet-traffic.md>)

Tags: [bgp](<https://devfeed.tech/tags/bgp.md>), [bug](<https://devfeed.tech/tags/bug.md>), [eos](<https://devfeed.tech/tags/eos.md>), [incident](<https://devfeed.tech/tags/incident.md>), [internet-traffic](<https://devfeed.tech/tags/internet-traffic.md>), [juniper](<https://devfeed.tech/tags/juniper.md>), [network](<https://devfeed.tech/tags/network.md>), [route](<https://devfeed.tech/tags/route.md>), [router](<https://devfeed.tech/tags/router.md>), [routing](<https://devfeed.tech/tags/routing.md>), [servers](<https://devfeed.tech/tags/servers.md>)

## AI overview

The article analyzes a May 20, 2025 BGP incident in which a corrupt BGP Prefix-SID attribute containing zeroed internal data interacted with JunOS and Arista EOS behavior. JunOS propagated the message, while Arista EOS devices reset sessions, causing routing instability and potentially brief connectivity loss for some networks.

## Source excerpt

benjojo reports: At 7AM (UTC) on Tuesday May 20th 2025 a BGP message was propagated that triggered surprising (to many) behaviours with two major BGP implementations that are often used for carrying internet traffic. This caused a large number of "internet facing" BGP sessions to automatically shut down, causing at the very least some routing instability, and at worst brief loss of connectivity for some networks. BGP implementations failing in various ways after seeing something incorrect/unexpected is definitely not a new thing...