Slashable offenses on Ethereum
Three primary categories:
- Double proposal — proposing two different blocks at the same slot. Rare; usually indicates a client bug or misconfigured failover.
- Surround vote / double vote — attesting to conflicting chains. Can happen if a validator is run simultaneously in two places (migration gone wrong) or a misconfigured signer.
- Double signing — signing two messages for the same slot. Catch-all for various protocol violations.
Inactivity penalties (extended downtime) are technically not slashing — they’re separate, smaller penalties. Actual slashing events are rare for competent operators.
Slashing penalties
On Ethereum:
- Initial penalty — 1/32 of effective balance (1 ETH for a full validator). Triggered the moment the slashing is detected.
- Correlation penalty — additional penalty proportional to how many other validators were slashed in the same 18-day window. A single misbehaving validator loses ~1 ETH; 500 simultaneously slashing could lose full stake each (due to correlation multiplier).
- Forced exit — slashed validators are queued for exit. They can’t continue validating.
- Minimum 36-day exit window — you can’t instantly leave after slashing.
The correlation multiplier makes Ethereum’s slashing design particularly punishing for mass correlated failures. A single validator bug that affects many operators could slash everyone running that client.
Slashing on other chains
- Cosmos chains — 5% slash for double-signing is typical. Liveness penalties (missing blocks) are smaller, ~1% cumulative.
- Solana — no slashing for downtime; theoretical slashing for double-voting exists but hasn’t been implemented in production.
- Polkadot — slashing percentage scales with offense severity; up to 100% for coordinated attacks.
Historical slashing events
Major events that actually happened:
- Lido’s operator slashing (October 2023) — a single Lido node operator (Launchnodes) was slashed due to an operational issue. Penalty was <0.5% of that operator’s stake; socialized across Lido stakers, the impact was tiny.
- Various small-operator slashings — happen occasionally. Almost all are operator error (migration mistakes, failover configuration) rather than deliberate attacks.
- Coordinated slashing events — haven’t happened at meaningful scale. Ethereum has been live as PoS since September 2022 without a major correlated slashing.
Risks and considerations
For solo stakers:
- Migration accidents — running the same validator on two machines simultaneously is the #1 slashing cause. Use slashing-protection databases; verify single-instance operation before starting.
- Client diversity — running minority clients reduces the blast radius if a major client has a bug causing correlated slashing.
- Test environments — never import a live validator key into a test setup. Many slashings have been migration mistakes where the validator was technically still running elsewhere.
For delegators:
- Slashing socializes across delegators. If you delegate to a misbehaving validator, you share the loss proportionally.
- Switch validators proactively if the one you chose has uptime issues or unusual behavior.
- Split delegation across multiple validators to cap single-validator exposure.
For restaked stake:
- Compounded slashing risk. Restaked ETH can be slashed both by Ethereum (for L1 misbehavior) and by each opted-in service on EigenLayer. Understand which services your restaked position is opted into.
Slashing is rare but catastrophic. The defenses are operational: careful migration procedures, monitoring, diversified delegation, and validator selection based on historical uptime and ethics.