Hack history / 2021 / Hack or exploit
Polygon
Hack or exploit on Dec 3, 2021 · Improper Access Control
SOURCES AGREE ON DATE AND LOSS · 3 SOURCES
Lost
$2M
dollars at the time
Returned
none listed
as the sources state it
Rank
#682
among thefts by dollars lost
What happened
White-hat hackers discovered a critical vulnerability in Polygon's PoS genesis contract MRC20 token where the transfer function lacked balance/allowance checks. This would have allowed stealing ~9.3 billion MATIC tokens. Before the fix was deployed, threat actor stole 801,601 MATIC tokens. White hat received $2.2M bug bounty for the disclosure.
Details
- Date
- Dec 3, 2021
- Kind
- Hack or exploit
- Method
- Improper Access Control
- How in
- Smart contract bug
- Target
- DeFi protocol
- Chains
- Polygon
Related incidents
Polygon 2024 · Hack or exploit · $140K
$1.25 million stolen in 2 months in Polygon NFT phishing scheme 2023 · Scam · $1.2M
Polygon zkEVM 2023 · Hack or exploit · undisclosed
Polygon & Fantom 2022 · Hack or exploit · undisclosed
Polygon Plasma Bridge 2021 · Hack or exploit · $2M
$1.25 million stolen in 2 months in Polygon NFT phishing scheme 2023 · Scam · $1.2M
Polygon zkEVM 2023 · Hack or exploit · undisclosed
Polygon & Fantom 2022 · Hack or exploit · undisclosed
Polygon Plasma Bridge 2021 · Hack or exploit · $2M
Cite this page
SwanBluechip, "Polygon hack, Dec 3, 2021: $2M lost", Crypto hack history, https://swan-hack-tracker.pages.dev/history/i/ht3ec72327da/ (data as of 2026-10-31).