Delegatecall Vulnerability

Overview

In EVM systems, delegatecall executes another contract’s code while preserving the caller’s address, storage, balance context, and original caller information. This enables proxy patterns and reusable libraries but grants the target code powerful influence over caller state.

Vulnerabilities arise from untrusted target addresses, incompatible storage layouts, unsafe initialization, selector collisions, compromised implementations, or upgrade authorization failures. Malicious code can overwrite owners, implementation slots, balances, or other critical variables.

Developers should restrict targets, use standardized proxy layouts, lock initializers, separate upgrade authority, review storage changes, and test every implementation transition. Verification must inspect the active implementation and proxy configuration rather than only the visible proxy address.

A delegatecall vulnerability lets external contract code execute in the caller’s storage context and corrupt state, privileges, or upgrade control. Delegatecall extends the caller’s authority to external code, making target trust, storage compatibility, initialization, and upgrades security-critical.

Assessment of Delegatecall Vulnerability should trace delegatecall vulnerability lets external contract code execute in the caller’s storage context and corrupt state, privileges, or upgrade control from prerequisite and entry point through observable impact on the affected service. A theoretical weakness or scanner result involving privileges, and upgrade control should not be reported as exploitation without corroborating logs, transactions, or configuration evidence. Prevention, detection, containment, and recovery for the Delegatecall weakness should be tested against the architecture associated with privileges, and upgrade control.

Retesting for Delegatecall Vulnerability should reproduce the Delegatecall weakness involving privileges, and upgrade control, examine adjacent paths, and verify the conditions for safely returning the affected service to normal operation.