CoinMarketCap Front End Compromised via Malicious Pop-Up Attack, Now Resolved

CoinMarketCap’s front end was briefly compromised on June 20, with visitors encountering unauthorized pop-up messages asking them to connect their crypto wallets. The incident was quickly flagged by members of the crypto community and confirmed by the CoinMarketCap team.

The platform urged users not to interact with any wallet connection prompts while the investigation was underway.

Root Cause Traced to Homepage Doodle Feature

Blockchain security firm Coinspect Security traced the root of the issue to a vulnerability in CoinMarketCap’s rotating homepage doodle feature. The backend API delivered manipulated JSON payloads that injected malicious JavaScript, causing pop-ups to appear and simulate wallet-verification requests.

Some users were also shown fake “exclusive airdrop” offers prompting them to connect wallets, a classic phishing vector used to drain crypto assets.

The malicious pop-up appeared briefly, lasting just around five minutes. By the time most users refreshed the site, the issue had been resolved and the homepage returned to normal.

CoinMarketCap Responds Swiftly

CoinMarketCap published a detailed update, confirming the breach and outlining mitigation efforts. According to the team:

On June 20, 2025, our security team identified a vulnerability related to a doodle image on our homepage. This image triggered malicious code through an API call, resulting in unexpected pop-ups.”

They added that once identified, the exploit was isolated and patched. CoinMarketCap stated that all systems are now fully operational and safe to use.

“We acted immediately to remove the problematic content, identified the root cause, and implemented comprehensive mitigation measures.”

Support teams are actively monitoring feedback and assisting users who may have been affected.

Incident Highlights Broader Cybersecurity Threats

The incident comes on the heels of a record-setting global password breach, with 16 billion compromised credentials exposed across dozens of datasets. That breach included login information for platforms like Facebook, Google, Apple, GitHub, and Telegram.

Given the scale of recent attacks, security experts are urging users to take precautions:

• Update passwords immediately, especially for accounts linked to crypto or financial services
• Use a password manager to generate strong, unique credentials
• Enable two-factor authentication wherever possible
• Avoid connecting wallets to unknown or suspicious web pop-ups