Deeply buried 16-year-old SQLite bug caused last year's Tailscale outages
Think your bugs are a pain to track? WAL-Reset took six months of hunting and development of a new logging tool to identify
In August 2025, Tailscale, a peer-to-peer networking service, experienced a series of unexpected outages. After six months of investigation, the team discovered the root cause was a 16-year-old SQLite bug. Tailscale software engineer Alex Chan explained that SQLite, which had been used as the primary database since 2022, caused the issue due to a rare data race affecting the checkpointing process.
This bug, known as the WAL-Reset bug, requires multiple database connections and manual checkpoints for its occurrence. The SQLite team created a new tool to investigate the issue, revealing the WAL-Reset bug. SQLite maintainers confirmed the bug existed since version 3.7.0 in 2010. SQLite recommends users update to a fixed version, but the team emphasized the bug is unlikely to occur in regular use.
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