Aztec Network is dealing with a second bridge-related hit this week. Protos reports the latest loss as about $2 million, after Sunday’s $2.2 million exploit tied to Aztec Connect.
In both cases, Aztec Labs says the affected contracts were “immutable” and had been “deprecated” in 2022 and 2023. That distinction matters. Deprecation often means “stop using it,” not “nobody can touch it.” On-chain, attackers don’t care what the team labels a contract.
What got drained and where the money sat
The newest incident targeted Aztec’s Private Rollup Bridge, specifically its escapeHatch function. Protos describes escapeHatch as an emergency withdrawal path. Users can pull assets held on the rollup directly from Ethereum through that mechanism.
A security researcher flagged the first signs of the loss. Protos names Vishal Singh as the person who first flagged the incident.
Yu Xian, founder of SlowMist, told Protos about three suspicious transactions draining the bridge. Protos says roughly $2.15 million was taken in 1,158 ether, 150,000 DAI, and 0.5 renBTC. Those funds came out while the escapeHatch was “open.”
The core claim from SlowMist is more specific than “something was wrong.” Protos says that during brief windows when the hatch was open, an attacker could trick the escapeHatch into releasing funds by using specific proofId and publicOutput parameters.
There’s a blunt lesson here. If an emergency valve has narrow intended inputs but wide acceptance in code, it won’t stay an emergency valve for long.
Why “deprecated” and “immutable” didn’t save anyone
Aztec Labs stressed in Protos’ reporting that the affected contracts were “immutable” and “deprecated” in 2022 and 2023.
Those words can both be true and still fail to protect users.
In Protos’ account, an investigation is now focused on “a potential exploit affecting a deprecated Aztec payments product from 2021.” Protos adds that about $2 million was transferred from the immutable smart contract in a specific transaction, with the tweet noting the deprecated product as an immutable stage 2 rollup sunset in 2022.
a potential exploit affecting a deprecated Aztec payments product from 2021.
That lines up with a pattern Protos flags earlier in the piece. Deprecated components tend to linger because teams cannot always unwind state without breaking integrations. If any funds remain in those contracts, attackers only need one mistake in the contract logic or parameter binding.
The repeated root cause: “public input binding issues”
Protos also cites analysis from BlockSec. The desk reports that both Sunday’s and Thursday’s incidents were caused by “public input binding issues,” even if they were not identical.
“Public input binding” is security shorthand for whether the contract ties cryptographic proofs to exactly the data it expects. If the proof inputs are not bound tightly enough to the output being released, you can get weird and catastrophic behavior in situations where the protocol assumes verifications mean safety.
This isn’t the first weekend where bridge logic became the weakest link. Protos references a rough weekend in DeFi where four hacks and three outages happened, and notes “bridge hacks back in vogue” after another 2026 total climbed.
Where the bridge-exploit tally stands
Protos places this week’s losses in a bigger year-to-date context. It says bridge-related exploits total 14 incidents this year, with over $340 million lost across bridge work.
The security picture is messy. Protos notes the hit rate “dropped off somewhat in recent weeks,” but also reports the community braced for Anthropic’s Mythos release and that its cybersecurity capabilities were “nerfed.” That last point reads like a reminder that attackers and defenders keep moving, even when headlines temporarily cool.
Here are the concrete details Protos included for this incident and Sunday’s loss context.
| Incident | Target | Amount drained (per Protos) | Asset mix (per Protos) | Stated status of affected contracts |
|---|---|---|---|---|
| Latest hack (June 18, 2026) | Aztec Private Rollup Bridge escapeHatch | ~ $2.0M, about $2.15M reported | 1,158 ETH, 150,000 DAI, 0.5 renBTC | “immutable” and “deprecated” (2022–2023) |
| Prior hack (Sunday) | Aztec Connect | $2.2M | Not listed in source text | Same “immutable” and “deprecated” framing |
What happens next
Protos says Aztec Labs is investigating a “potential exploit” tied to a deprecated Aztec payments product from 2021. It also reports the security investigation includes the possibility that an escapeHatch parameter handling flaw enabled withdrawals.
For operators and users, the practical takeaway is less about Aztec specifically and more about how bridge and rollup emergency mechanisms get treated. Emergency functions are designed for failure modes. They still need to fail safely when parameter windows open, even if the system claims the underlying contracts are deprecated or immutable.