{"api_version":"1","generated_at":"2026-04-23T03:48:17+00:00","cve":"CVE-2026-33471","urls":{"html":"https://cve.report/CVE-2026-33471","api":"https://cve.report/api/cve/CVE-2026-33471.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-33471","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-33471"},"summary":{"title":"nimiq-block has skip block quorum bypass via out-of-range BitSet indices & u16 truncation","description":"nimiq-block contains block primitives to be used in Nimiq's Rust implementation. `SkipBlockProof::verify` computes its quorum check using `BitSet.len()`, then iterates `BitSet` indices and casts each `usize` index to `u16` (`slot as u16`) for slot lookup. Prior to version 1.3.0, if an attacker can get a `SkipBlockProof` verified where `MultiSignature.signers` contains out-of-range indices spaced by 65536, these indices inflate `len()` but collide onto the same in-range `u16` slot during aggregation. This makes it possible for a malicious validator with far fewer than `2f+1` real signer slots to pass skip block proof verification by multiplying a single BLS signature by the same factor. The patch for this vulnerability is included as part of v1.3.0. 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Prior to version 1.3.0, if an attacker can get a `SkipBlockProof` verified where `MultiSignature.signers` contains out-of-range indices spaced by 65536, these indices inflate `len()` but collide onto the same in-range `u16` slot during aggregation. This makes it possible for a malicious validator with far fewer than `2f+1` real signer slots to pass skip block proof verification by multiplying a single BLS signature by the same factor. The patch for this vulnerability is included as part of v1.3.0. No known workarounds are available.","Type":"Description","Title":"nimiq-block has skip block quorum bypass via out-of-range BitSet"}]}}}