Incident Overview
On May 11, 2026, Ink Finance’s Workspace Treasury Proxy on Polygon was exploited for approximately $140,000 USDT. The attack leveraged a missing access control check in a payroll distribution contract, allowing the attacker to register themselves as a whitelisted claimer. The exploit was amplified by a $25,000 flash loan to drain the treasury’s dormant funds.
The exploit was rooted in a critical logic flaw within the addUsers function of the protocol's PayrollDistribution contract. This function lacked proper access control, permitting any user to register addresses for existing reward "drops" and set arbitrary payment amounts. The attacker deployed a malicious contract and registered it as an eligible claimer with an inflated totalAmount.
To maximize the payout, the attacker utilized a $25,000 flash loan from Balancer V2 to satisfy balance-sensitive checks within the claim path. Because the treasury proxy implicitly trusted the approval signaled by the vulnerable controller, it released approximately $140,000 in USDT to the attacker. The funds were originally sourced via the Railgun privacy protocol on Ethereum before being bridged to Polygon shortly before the attack.
Victim Proxy: 0xa184Af4B…a96Ee4
Vulnerable Contract: 0xef2c77f3…433494
Attacker Address: 0x90b14759…a87ee2
Incident Report
Protocol Information
Market Context at Time of Hack
What the Attacker Needed to Succeed
Understanding the prerequisites for this type of attack helps auditors identify protocols that are most at risk and helps developers build better defenses.
What Auditors Should Check
If you're auditing a protocol with similar architecture to Ink Finance, these are the critical security checks that could have prevented this incident (May 2026).
- Verify all logic paths related to Access Control are guarded by proper access controls and input validation - see the Access Control Attacks attack class for patterns
- Review privileged functions (owner, admin, governance) for potential abuse vectors - centralization risks should be documented and bounded with timelocks or multi-sigs
Master these auditing techniques with hands-on labs and real exploit scenarios in the Smart Contract Hacking course.
Free TrialSecurity Audit History
- Audit Report 1 Report
Related Attack Classes
The technique used in this hack maps to these vulnerability classes in our security curriculum:
Sources & References
Learn to Prevent the Next Ink Finance
The Ink Finance hack is one of many attacks that skilled auditors are trained to detect before deployment. Master real exploit patterns and defense techniques with hands-on Web3 security training.