Polymarket Suffers $3 Million Crypto Drain via Third-Party Vendor Compromise
Prediction market platform Polymarket disclosed a breach where hackers compromised a third-party vendor. The attackers injected malicious code into the Polymarket website for some users, leading to the draining of approximately $3 million in pUSD (USDC-backed) from at least 11 user wallets. The stolen funds were subsequently swapped and moved to Ethereum. Polymarket has contained the incident, committed to full refunds for affected users, and is in the process of notifying victims. This incident highlights supply-chain vulnerabilities in web frontends and crypto platforms.
Signal context
First seen: Jun 28, 2026
Last updated: Jun 29, 2026
Status: Public signal
Key points
- Polymarket, a prediction market platform, disclosed a data breach.
- Hackers compromised a third-party vendor and injected malicious code into the website.
- Approximately $3 million in pUSD (USDC-backed) drained from at least 11 user wallets.
Signal analysis
BetaThis analysis groups the signal by industry, likely incident action and impacted security area. It helps compare this signal with other published signals without treating the labels as final determinations.
Sector: Information
Likely country: Location not provided
The feed marks multiple actor roles. Treat this as a review signal rather than a final attribution.
- Source type: outside the affected organization
- Source type: supplier or third-party involvement
Impact area: Confidentiality
- 29 signals in the same sector
- 93 signals with the same likely impact area
- 1 signal linked to this organization/domain
External sources
Security Check-in Quick Hits: Russian Messaging Phishing, Polymarket Crypto Drain, and Tata Supplier Breach Spotlight Persistent Supply Chain and Social Engineering Risks - Rod's Bloghttps://rodsblog.com/2026/06/28/security-check-in-quick-hits-russian-messaging-phishing-polymarket-crypto-drain-and-tata-supplier-breach-spotlight-persistent-supply-chain-and-social-engineering-risks/Public source from rodsblog.com.
Cybercrime Wire For Jun. 27-28, 2026. Weekend Update. WCYB Digital Radio. - YouTubehttps://www.youtube.com/watch?v=dQw4w9WgXcQPublic source from youtube.com.
$3 Million Reportedly Stolen in Polymarket Hack - SecurityWeekhttps://www.securityweek.com/3-million-reportedly-stolen-in-polymarket-hack/Public source from securityweek.com.
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