Solana (SOL) came close to losing transaction finality on August 12 after a routing failure at infrastructure provider Teraswitch briefly took validators representing nearly 29 percent of staked SOL offline.
Blocks kept being produced, and the offline share stayed several points below the level that would have stopped the network from making transactions irreversible.
The problem began with a stale default route on a Miami edge router.
Routine transit-provider maintenance activated that path.
A routing-policy error then stripped attributes and applied a no-export instruction toward Europe and Asia-Pacific.
An Amsterdam route reflector distributed the malformed default across Teraswitch sites.
Edge routers at a dozen locations treated the invalid route as locally originated, preferred it over working local defaults, and advertised it into the data-center core, which rejected it.
With no valid outbound path, facilities in London, Amsterdam, Dublin, Frankfurt, Singapore, and Tokyo lost internet and inter-site connectivity.
North American sites were not affected.
At peak impact, about 28.83 percent of network stake went delinquent.
Solana’s consensus requires more than two-thirds of stake to vote for a block to become final.
If more than 33.34 percent of stake drops offline at the same time, finality stops even while leaders continue proposing blocks.
The outage therefore approached that halt line—roughly 4 to 5 percentage points short—but never crossed it.Independent telemetry showed the cost of that near-miss.
Skipped slots rose above 32 percent.
Non-vote throughput fell from a typical 1,100–1,300 transactions per second to below 300.
Newly produced blocks waited about half an hour before reaching finality.
Once routing reconverged, the backlog cleared.
Teraswitch restored provider traffic about 33 minutes after the first alarm and later applied hardening so an invalid remote default could no longer prevent sites from using healthy local edge routers.
Concentration amplified the blast radius.
One autonomous system associated with Teraswitch hosted more than a quarter of all staked SOL, above the 25 percent ceiling used by the Solana Foundation’s delegation program, and most of that stake went dark together.
The Foundation later said Teraswitch had carried as much as 38 percent of network stake in 2025 and that earlier work had already reduced the share below 30 percent before August 12.
That reduction left just enough voting power online.
Few operators automatically failed over; most waited for the original routes to recover.
Even Devnet, which lost a far larger fraction of stake in the same window, came back without a coordinated restart.
The Foundation framed the episode as evidence that prior diversification had worked: users who did not need instant settlement may have seen little more than slower confirmations. The incident still left infrastructure diversity and routing observability as open resilience tests. Additional route monitoring remained in progress after the postmortem.