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A major Smart contract exploit has rocked the Truebit protocol, wiping out roughly $26 million in value and sending its TRU token into a near-total collapse. The incident underscores a harsh reality for crypto markets in 2026: even long-running blockchain projects are not immune to basic coding failures.
The exploit, first reported by Cointelegraph, stemmed from a flaw in Truebit’s token purchase contract that allowed an attacker to mint massive amounts of TRU tokens for virtually nothing. Within hours, the newly created supply flooded the market, triggering a staggering 99% price crash.
Blockchain security firm SlowMist, which conducted a post-mortem analysis, described the incident as a textbook Smart contract exploit rooted in outdated development practices. “The attacker was able to mint massive amounts of tokens without paying any ETH,” SlowMist said, pointing to a critical arithmetic error inside the protocol’s smart-contract logic.
According to SlowMist, the Truebit Purchase contract failed to include overflow protection when performing integer addition. Because the contract was compiled using Solidity version 0.6.10, it lacked the automatic overflow checks introduced in later versions of the language.
“Due to a lack of overflow protection in an integer addition operation, the contract produced an incorrect result when calculating the amount of ETH required to mint TRU tokens,” SlowMist explained. That error caused the calculated price to “wrap around” to a value close to zero, effectively allowing the attacker to mint $26 million worth of tokens at negligible cost.
This Smart contract exploit highlights how a single unchecked calculation can undermine years of development. Truebit launched on Ethereum’s mainnet in April 2021 and had operated for nearly five years without a comparable incident.
The aftermath was swift and brutal. As the attacker dumped newly minted tokens, TRU’s price collapsed by roughly 99%, wiping out market confidence almost instantly. Analysts say the Truebit Smart contract exploit reinforces concerns about legacy contracts that have not been fully upgraded to modern security standards.
“Longevity doesn’t equal safety,” said a senior blockchain auditor familiar with the incident. “Older contracts often predate key safeguards. Attackers actively hunt for these weaknesses.”
The exploit also reignited debate around best practices for maintaining long-lived protocols. Security researchers have long warned that failing to refactor or redeploy contracts can leave projects exposed to precisely this kind of Smart contract exploit.
The Truebit incident comes amid growing attention on automated vulnerability discovery. Late last year, artificial intelligence firm Anthropic revealed that commercially available AI agents were able to identify and develop exploits worth $4.6 million across various smart contracts.
According to Anthropic’s red-team research, models including Claude Opus 4.5, Claude Sonnet 4.5, and OpenAI’s GPT-5 successfully uncovered exploitable flaws during controlled testing. Researchers said the findings demonstrate how quickly Smart contract exploit discovery is becoming automated.
“These tools are designed to help defenders, but the same techniques can be misused by attackers,” Anthropic warned, noting that time-to-exploit is shrinking rapidly.
Data from SlowMist’s year-end report shows that Smart contract exploit incidents were the single largest attack vector in crypto during 2025. The firm recorded 56 smart-contract-related security incidents, surpassing account compromises, which totaled 50 cases.
In percentage terms, contract vulnerabilities accounted for 30.5% of all crypto exploits last year. By comparison, hacked X (formerly Twitter) accounts made up 24%, while private key leaks represented 8.5%.
“These numbers show that the industry still struggles with secure contract design,” SlowMist said. “The Truebit Smart contract exploit fits squarely into this broader trend.”
While protocol-level attacks remain prevalent, attackers are also diversifying. Blockchain security platform CertiK reported that crypto phishing scams emerged as the second-largest threat of 2025, costing investors a cumulative $722 million across 248 incidents.
Unlike a Smart contract exploit, phishing attacks rely on social engineering rather than code vulnerabilities. Victims are tricked into clicking malicious links or signing fraudulent transactions that expose private keys.
Even so, the data offers a small silver lining. CertiK noted that phishing losses were down 38% from the roughly $1 billion stolen in 2024, suggesting growing user awareness. Smart contract failures, however, continue to deliver outsized damage in single incidents, as the Truebit case illustrates.
Security experts say the Truebit Smart contract exploit reinforces several hard lessons for the industry. First, older Solidity versions without built-in overflow checks remain dangerous if contracts are not properly audited or upgraded. Second, automated testing—whether via AI or formal verification—must become standard practice, not an optional expense.
“Every protocol should assume attackers are using advanced tools,” said a DeFi security consultant. “If your contracts haven’t been stress-tested against modern exploit techniques, you’re already behind.”
For investors, the message is equally stark. Even established projects can unravel overnight due to a single Smart contract exploit. As crypto adoption grows, so does the cost of complacency.
The Truebit incident may fade from headlines, but its implications will linger. Until rigorous security becomes the norm, Smart contract exploit risks will remain one of the industry’s most persistent—and costly—threats.
