Threats affecting pkg:cargo/github/nimiq/nimiq-block

CVE-2026-33471 is a critical vulnerability in the nimiq-block Rust implementation prior to version 1.3.0. It involves improper input validation in the SkipBlockProof::verify function, where out-of-range signer indices can be exploited to bypass quorum checks. This allows a malicious validator with fewer than the required number of signer slots to pass verification by manipulating signature aggregation. The vulnerability has a CVSS score of 9.6, indicating high impact on integrity and availability. A patch fixing this issue was included in version 1.3.0.