Unidentified Base vault (Aave V3 wstETH position) hack — October 2026

An unidentified vault on Base that held a leveraged wstETH position on Aave V3 lost 1,783.067 wstETH, about $5.99m, on 4 October 2026. The vault is an upgradeable proxy contract owned by a Safe multisig that needs three of its seven signers to act. No protocol, fund or company has said the vault is theirs, and none of the seven signers has been publicly identified. Blockaid flagged the attack at 09:20 UTC, when about $2.02m had gone, and PeckShield, CertiK and ExVul later put the total at about 1,783 wstETH. Neither Aave's core contracts nor the Base network were compromised.

The vault let whitelisted contracts move its Aave position. According to ExVul, the owner Safe removed the attacker's newly deployed contract from the whitelist at 08:52 UTC and re-enabled it at 08:53, both changes carrying valid signatures from the Safe's existing signers. This registry read from the chain that both transactions were submitted by the address that had deployed the vault in February 2025, while the Safe's earlier transactions had been submitted by a different address. From 08:55 UTC the attacker's contract pulled the vault's Aave receipt tokens, aBaswstETH, in six transfers: a test of one token, then 100, three of 500 and a final 182.067 between 09:08 and 09:12 UTC. The attacker redeemed the 1,783.067 tokens through Aave for wstETH at 09:23 UTC and moved the wstETH to another address at 10:47. How the signatures for the whitelist change were obtained, whether through compromised keys, a manipulated signing process or something else, has not been disclosed.

The amount recorded is the 1,783.067 aBaswstETH that left the vault, which this registry read from its token transfers, valued at the wstETH price of those minutes, about $3,360. When this registry checked later on 4 October, the vault still held about $31.8m of collateral against $7.8m of debt on Aave, so the theft did not push it into liquidation. No owner had come forward by the evening of 4 October, and no post-mortem, freeze, recovery or bounty offer had been announced.