An attacker who is not a council member can forge a SmartOp::Vote transaction that satisfies signature verification, nonce and balance checks but is not authorized until after the state has already been mutated. This ordering flaw allows the transaction to change the blockchain state before the authorization check, corrupting a critical supply invariant and triggering a fatal halt in the network. The vulnerability manifests as an authorization weakness (CWE‑696), coupled with an unchecked state mutation that can lead to denial of service. It does not directly expose confidential data, but the resulting halt disrupts the availability and integrity of the network, potentially causing loss of funds and service.

The vulnerability affects UltraDAGcom’s core implementation, specifically version 0.1 as disclosed by the vendor. No other versions or products are listed as impacted in the CNA data.

The CVSS score of 8.8 classifies the flaw as high severity. The EPSS score is not provided, but the lack of any restriction on who can submit signed SmartOp::Vote transactions implies a low barrier to exploitation. The vulnerability is not listed in CISA’s KEV, suggesting no known widespread exploitation at this time. Attackers only need the ability to sign a transaction with a non‑council key, which is reportedly doable under the existing rules. Consequently, this flaw is likely to be exploited in environments that run the unpatched UltraDAGcore 0.1 network.