Hack history / 2021 / Hack or exploit
Polygon Plasma Bridge
Hack or exploit on Oct 21, 2021 · Double Spend Attack
ONE SOURCE · 1 SOURCE
Lost
$2M
dollars at the time
Returned
none listed
as the sources state it
Rank
#707
among thefts by dollars lost
What happened
Bug bounty platform Immunefi says white hat hacker Gerhard Wagner submitted a critical vulnerability affecting the Polygon Plasma Bridge on October 5, 2021 that allows attackers to withdraw their burn transactions from the bridge multiple times for up to 223 times. About $850 million is at risk, and an attack with just $100,000 would result in a loss of $22.3 million. Polygon confirmed the bug and immediately began fixing the underlying issue, which was resolved within a week. Polygon agreed to pay up to $2 million for the submission.
Details
- Date
- Oct 21, 2021
- Kind
- Hack or exploit
- Method
- Double Spend Attack
- How in
- Bridge and cross-chain
- Target
- not stated
- Chains
- Polygon
Reported by
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Polygon zkEVM 2023 · Hack or exploit · undisclosed
Polygon & Fantom 2022 · Hack or exploit · undisclosed
Polygon 2024 · Hack or exploit · $140K
$1.25 million stolen in 2 months in Polygon NFT phishing scheme 2023 · Scam · $1.2M
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Polygon & Fantom 2022 · Hack or exploit · undisclosed
Cite this page
SwanBluechip, "Polygon Plasma Bridge hack, Oct 21, 2021: $2M lost", Crypto hack history, https://swan-hack-tracker.pages.dev/history/i/hte8dbc438b4/ (data as of 2026-10-31).