How much was lost in the US Permissionless Dollar hack?

The US Permissionless Dollar hack resulted in $1.0M in losses on December 04, 2025.

What attack technique was used in the US Permissionless Dollar exploit?

The US Permissionless Dollar exploit utilized "CPIMP" proxy front-run. Understanding this attack vector is critical for smart contract auditors and developers building secure DeFi protocols.

How can developers prevent similar smart contract attacks?

Preventing smart contract hacks requires a combination of secure coding practices, thorough security audits, and understanding common attack vectors like reentrancy, oracle manipulation, and access control flaws. Smart Contract Hacking (SCH) provides hands-on training to help developers and auditors identify and prevent vulnerabilities before deployment.

US Permissionless Dollar Hack

TOTAL LOST $1.0M

Medium Dec 04, 2025 "CPIMP" proxy front-run ethereum

Affected Chain ethereum Incident surface

Recovered - No recovery reported

All-Time Rank #833 By amount stolen

Year 2025 Incident year

Incident Report

Protocol / Project US Permissionless Dollar

Date of Incident December 04, 2025

Affected Chain(s) ethereum

Attack Technique "CPIMP" proxy front-run

Classification Protocol Logic

Primary Source View Post-Mortem

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.

Technical Knowledge Deep understanding of "cpimp" proxy front-run and Solidity and EVM internals

Capital Required Seed capital to cover gas and initial position setup

On-Chain Access Ability to interact with ethereum smart contracts and deploy a custom exploit contract

Protocol Analysis Identification of the exploitable vulnerability in US Permissionless Dollar's contract logic - root cause: protocol logic

Execution Speed Precise transaction ordering and timing including MEV-awareness for frontrunning

Obfuscation Plan A strategy to launder and move stolen funds - typically through mixers, cross-chain bridges, or decentralized DEX swaps to resist tracing

What Auditors Should Check

Could this have been caught in audit? Likely — with a thorough "CPIMP" proxy front-run audit checklist and test coverage

If you're auditing a protocol with similar architecture to US Permissionless Dollar, these are the critical security checks that could have prevented this incident (December 2025).

Verify all logic paths related to "CPIMP" proxy front-run are guarded by proper access controls and input validation
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.

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Sources & References

01
Source 1 https://x.com/USPD_io/status/1996711283446464598

Threat Assessment

Severity Level

MEDIUM

Attack Vector "CPIMP" proxy front-run
Root Cause Protocol Logic
Year 2025

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