Syscoin said its bridge remains paused after a security incident created approximately 5 billion unauthorized SYS through the project’s UTXO bridge path. The project disclosed the incident in a preliminary postmortem published on X on June 7, 2026, where it said the bridge relay path incorrectly accepted or interpreted a transaction proof.
The exact time of the bridge pause was not separately disclosed in the accessible postmortem text. The safest timestamp is that the bridge was confirmed as paused by the time Syscoin posted its June 7 postmortem.
Preliminary Postmortem: Syscoin Bridge Incident
We want to provide the community with a preliminary update regarding the recent Syscoin bridge incident involving approximately 5B SYS.
The Syscoin bridge is currently paused while the team investigates, finalizes the fix, and…
— Syscoin (@syscoin) June 7, 2026
Validation Issue Created Unauthorized UTXO Output
According to Syscoin’s preliminary postmortem, the attacker exploited a validation issue in the bridge flow, causing the system to treat a fraudulent transaction proof as valid. That failure created an unauthorized output of roughly 5 billion SYS on the UTXO side, rather than draining a previously existing user wallet balance.
Syscoin said the affected funds were first sent to one UTXO address before being spent and split into other outputs. Public reports attribute the initial destination only as sys1qgaelv…9wvcw, with later tainted balances described as roughly 4 billion SYS in one address and 1 billion SYS in another; full UTXO addresses and transaction hashes were not exposed.
The status of the fix should also be framed carefully. Syscoin said it had identified the affected validation path and had a fix in place.
Exchanges Asked to Watch Tainted UTXOs
The exchange-containment detail comes from Syscoin’s own postmortem as relayed by multiple market reports, not from separate exchange announcements. Syscoin contacted exchanges and partners and asked them to freeze, blacklist or closely monitor deposits tied to the tainted UTXO trail and descendant spends.
Syscoin was coordinating with exchanges and ecosystem partners to prevent contaminated UTXOs from being deposited, traded or further distributed. The team contacted multiple exchanges and partners to request freezing or monitoring of funds related to the contaminated UTXO, a remediation plan had been developed and prioritized for implementation.
Syscoin has urged users not to interact with the bridge while operations remain suspended. For now, the confirmed operating picture is narrow: the bridge is paused, the validation path has been identified, the fix is still under implementation and review, and the tainted SYS trail is being monitored with exchange partners.