Syscoin’s bridge suffered an exploit after a transaction-proof validation flaw allowed manipulated data to pass verification checks.
According to the project’s preliminary postmortem, the bridge incorrectly accepted or interpreted a transaction proof. The error created roughly 5 billion unauthorized SYS through the UTXO bridge path.
The attacker later split the funds into two tainted addresses holding approximately 4 billion SYS and 1 billion SYS.
The team stated that no private keys were compromised during the incident.
Instead, the exploit stemmed from a validation failure inside the bridge’s proof-verification process. Syscoin paused the bridge, identified the affected validation path, and deployed a fix while tracing the funds.
