Safe Transaction Failure Modes and GS0XX Error Diagnostics

Gas required exceeds allowance or gas limit too low

Executors, relayers, wallet integrators

Verify gas estimation logic; check if refundReceiver is set correctly; simulate with higher gas limit

Threshold not met; insufficient owner confirmations

Signers, custodian teams, DAO operators

Audit approvedHashes mapping on-chain; confirm off-chain signature collection completed; verify signer set against current owner list

Transaction hash already executed or nonce already used

Automated systems, trading bots, treasury managers

Check execution history for duplicate nonce; verify nonce queue is not blocked by pending transaction

Invalid owner signature or signature ordering mismatch

MPC providers, HSM integrators, wallet teams

Validate EIP-712 domain separator values; confirm signature r/s/v concatenation order; check for signer address mismatch

Module or guard reverted execution

Module developers, Safe admins, security engineers

Trace module or guard revert reason via Tenderly; verify module is not paused or deprecated; check guard state conditions

Delegatecall to non-self address or untrusted module

Module developers, protocol architects

Confirm Operation enum is set to DelegateCall only for self-calls or explicitly allowed modules; review guard logic

Fallback handler misconfigured or incompatible

Safe admins upgrading handlers, ERC-4337 integrators

Verify fallback handler address matches canonical deployment for Safe version; test token callback and ERC-4337 compatibility

Contract call reverted during execution

DeFi protocol operators, treasury managers

Simulate transaction against target contract; check for slippage, access control, or state-change revert; verify target contract is not paused

Insufficient gas limit specified for a multi-step operation or complex module interaction. The gas sent with the transaction is lower than what the Safe's execTransaction logic requires.

Treasury operators, DAO tooling teams, relayers

Simulate the transaction via Tenderly or a trace-level RPC call to determine the actual gas used. Increase the safeTxGas parameter and re-submit. Chainscore can model gas requirements for complex execution paths.

A nonce has been reused, or a previously executed transaction payload is being re-submitted. Often occurs when multiple signers independently trigger execution.

Custodians, multi-sig coordinators, automated bots

Verify the current nonce via the Safe contract. Implement a coordination mechanism to ensure only one party submits the final execution. Review off-chain confirmation logic to prevent race conditions.

The signature verification logic failed because the recovered signer address is not a current owner of the Safe, or the owner set changed between signature collection and execution.

Wallet integrators, governance tooling, key management teams

Re-query the live owner set from the contract before execution. Ensure signature-collection pipelines invalidate cached owner lists after any AddOwner or RemoveOwner event. Chainscore can audit signature-verification pipelines.

The number of valid unique signatures collected is below the required threshold. This can happen if an owner is removed after signing, or if a packed signature contains duplicates.

Multi-sig coordinators, DAO operations, custody platforms

Monitor for quorum changes between signature collection and execution. Validate the uniqueness of signatures in the packed bytes before broadcasting. Implement pre-execution threshold checks.

An EIP-1271 contract signature was provided, but the signature bytes point to an invalid location or the contract returned an unexpected magic value. Common with misconfigured smart contract wallets.

Module developers, smart contract wallet teams, protocol integrators

Verify that the signing contract correctly implements isValidSignature and returns the EIP-1271 magic value. Test the contract signature path in isolation. Chainscore can review EIP-1271 implementations.

A transaction targets the Safe itself with a data payload intended for a fallback handler, but the fallback handler address is set to the zero address.

Safe administrators, deployment tooling, protocol operators

Verify the fallback handler configuration via getFallbackHandler(). If required for token callbacks or ERC-4337, set it to the correct canonical handler address. Chainscore can audit fallback handler configurations.

An operation initiated by an enabled module reverted. The root cause is internal to the module's logic, not the Safe's core execution path.

Module developers, treasury operators, risk teams

Debug the module's internal transaction using the original failure reason from the inner call. Isolate the module's state and permissions. Chainscore can perform root-cause analysis on module execution failures.

A delegatecall operation to an untrusted or misconfigured contract modified the Safe's storage layout unexpectedly, causing subsequent calls to fail or behave erratically.

Security engineers, module developers, protocol architects

Restrict delegatecall targets to self-calls or rigorously audited modules. Simulate all delegatecall paths in a forked environment. Chainscore can review delegatecall patterns for context hijacking risks.