Monitoring

Siren

MEDIUMPolygon·Reentrancy·#375 all-time
$3.5M stolenFriday, September 3, 2021 · 1878 days ago

Corpus updated 2026-10-25

What happened

  • Siren, a defi protocol, lost $3.5M on September 3, 2021.

  • The 63rd largest of the 127 incidents recorded in 2021: under 1% of the $2.87B lost to hacks that year.

  • Reentrancy is behind 58 recorded incidents totalling $385.3M; this is the 18th largest of them.

Cite this record

Monitoring Room, "Siren hack — $3.5M stolen", incident record, data: DefiLlama hacks dataset, as of 2026-10-25 08:00 UTC. https://monitoringroom.com/situation/crypto-hack/siren

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8/30/2021$18.8M
DAO Maker Vesting
9/4/2021$4.0M
Bilaxy
8/29/2021$21.7M
Zabu Finance
9/12/2021$3.2M
xToken
8/29/2021$4.5M
NowSwap
9/15/2021$1.1M
← All incidents

Source: DefiLlama · 1317 recorded incidents · data as of 2026-10-25 08:00 UTC