Solana Nearly Lost Transaction Finality After Teraswitch Routing Misconfiguration

CoinDesk reported that Solana briefly came close to a breakdown in transaction finality early Wednesday after a routing configuration problem at custodial service Teraswitch knocked 28.83% of staked SOL offline. Solana stops confirming blocks when about 33.34% of staked tokens become unreachable, leaving the network just 4.51 percentage points from the finality cutoff. Marinade Finance estimated the incident reached roughly 86% of the network's "stall threshold." Teraswitch said the disruption stemmed from a single routing failure. A default route originating from its Miami site lost its metric and community attributes as it propagated, then was redistributed to European and Asia-Pacific nodes through an Amsterdam route reflector. An edge router treated the route as locally generated and prioritized it over the normal exit path, while the data center core network rejected it as invalid. That sequence temporarily removed valid forwarding paths across 12 locations, including London, Amsterdam, Dublin, Frankfurt, Singapore and Tokyo. North America was not affected. Engineers isolated the problem in about 10 minutes, and service was restored at 04:16:15 UTC. Marinade said around 90 validators were impacted and collectively missed 333 SOL in rewards. Its analysis found the outage was heavily concentrated within a single autonomous system, AS20326, which holds 118.89 million SOL, or about 27.34% of total network stake. Marinade estimated 94% of that stake went offline during the event, exceeding the Solana Foundation's delegated program cap of 25% per autonomous system. Marinade also noted that 59 validators representing about 80.2 million SOL recovered within the same window in Amsterdam, Frankfurt and Tokyo, suggesting many were waiting for routes to reconverge rather than failing over to alternative paths. Solana's second-largest validator, Helius, was offline for 33 minutes. Marinade said an additional 14.1 million SOL was offline at the same time across custodial environments such as latitude.sh, Limestone, Butterfly Research and Allnodes, a pattern it said cannot be fully explained by the available data. The firm warned that assessing diversification solely through custodian classifications may understate the risk of large numbers of validators going offline simultaneously in a shared failure. Marinade also flagged concentration in its own allocation approach, noting that two-thirds of its delegated stake sits in four autonomous systems, with AS395201 alone accounting for 36.94%. The protocol said it will revisit concentration limits by network and data center and begin disclosing whether validators support hot swapping and automated failover. The 333 SOL in missed rewards is expected to be covered by validator stakes after the current epoch ends. Marinade cautioned that if the offline rate rises above one-third at that time, confirmations for all SOL holders would halt, and no staking mechanism exists to offset such a system-wide outcome. Solana's last full network outage occurred in February 2024 and took nearly five hours to restore.