Secret

Polymarket

Aztec

Humanity

A third-party vendor compromise discovered Thursday allowed attackers to inject a malicious script into Polymarket's frontend, affecting multiple users.
Blockchain analyst Specter <a href="https://x.com/SpecterAnalyst/status/2070152064051605517" rel="noopener noreferrer nofollow">said</a> the malicious script appeared to facilitate a phishing attack that drained an estimated $2.94 million from at least 11 Polymarket user wallets.
Polymarket <a href="https://x.com/polymarkettrade/status/2070155882906730671" rel="noopener noreferrer nofollow">said</a> on X that the compromise has been contained and that the affected dependency has been removed. It added that users would be fully refunded.
Cointelegraph has approached Polymarket for comment but did not receive a response before publication.
The attack was the 89th reported crypto security breach of the second quarter, according to <a href="https://defillama.com/hacks" rel="noopener noreferrer nofollow">DefiLlama</a> data, extending <a href="https://cointelegraph.com/news/q2-2026-most-hacked-quarter-record-83-incidents" rel="noopener noreferrer nofollow">the most-hacked quarter on record</a> by incident count.
<img alt="" height="570" src="https://s3-images.ctmedia.io/media/content/pasted-image-1700.png" width="920">
Source: <a href="https://x.com/SpecterAnalyst/status/2070152064051605517" rel="noopener noreferrer nofollow">Specter</a>
<h2 id="crypto-exploit-losses-reach-74-9m-across-29-june-incidents">Crypto exploit losses reach $74.9M across 29 June incidents</h2>
Crypto exploit losses climbed to $74.9 million across 29 reported incidents in June, surpassing May’s $60.5 million total but remaining far below April’s $644 million, according to DefiLlama data.
<img alt="" height="377" src="https://s3-images.ctmedia.io/media/content/pasted-image-1701.png" width="1079">
Total value hacked by monthly sum, 1-year chart. Source: DefiLlama.
The largest June incidents included the <a href="https://cointelegraph.com/news/humanity-protocol-laptop-bridge-exploit-h-token" rel="noopener noreferrer nofollow">$36 million Humanity Protocol exploit</a>, the <a href="https://cointelegraph.com/news/secret-network-bridge-exploited-infinite-mint-bug" rel="noopener noreferrer nofollow">$4.7 million Secret Network bridge exploit</a>, <a href="https://cointelegraph.com/news/aztec-exploited-21-million-previous-hack-slowmist" rel="noopener noreferrer nofollow">two separate Aztec exploits</a> worth $2.1 million each and <a href="https://cointelegraph.com/news/taiko-urges-users-to-withdraw-as-bridge-exploit-drains-17m" rel="noopener noreferrer nofollow">a $1.7 million bridge exploit</a> on Taiko.
Related: <a href="https://cointelegraph.com/news/polymarket-first-crypto-touchpoint-world-cup-bettors" rel="noopener noreferrer nofollow">About 60% of World Cup bettors on Polymarket are first-time crypto users</a>
Over the past 30 days, private key compromises accounted for 43% of reported exploit losses, making them the leading attack vector, according to DefiLlama. Fake proof exploits accounted for 10%, followed by reverse MEV honeypots at 8%, which present deceptive trading opportunities to lure and manipulate automated trading bots.
About a month before Polymarket's latest attack, the prediction market disclosed a separate $600,000 exploit that was traced to <a href="https://cointelegraph.com/news/polymarket-uma-adapter-appears-exploited-520k-zachxbt" rel="noopener noreferrer nofollow">a six-year-old private key</a> used for internal top-up operations. Josh Stevens, Polymarket's vice president of engineering, <a href="https://x.com/devjoshstevens/status/2057768173915484505" rel="noopener noreferrer nofollow">said</a> the platform's contracts and user funds remained safe and that all permissions tied to the key had since been revoked.
<img alt="" height="447" src="https://s3-images.ctmedia.io/media/content/pasted-image-1702.png" width="1086">
Total value hacked by technique over the past 30 days. Source: DefiLlama
Polymarket currently holds over $450 million in total value locked, up 301% from $112 million a year ago, <a href="https://defillama.com/protocol/polymarket-international" rel="noopener noreferrer nofollow">according</a> to DefiLlama.
Magazine: <a href="https://cointelegraph-magazine.com/anger-grows-polymarket-bets-iran-war/" rel="noopener noreferrer nofollow">Should users be allowed to bet on war and death in prediction markets?</a>

Polymarket hit by $2.9M theft, users to be refunded

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