{"id":"CVE-2026-33471","sourceIdentifier":"security-advisories@github.com","published":"2026-04-22T20:16:40.317","lastModified":"2026-06-17T10:37:33.267","vulnStatus":"Analyzed","cveTags":[],"descriptions":[{"lang":"en","value":"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. No known workarounds are available."}],"affected":[{"source":"security-advisories@github.com","affectedData":[{"vendor":"nimiq","product":"nimiq-block","versions":[{"version":"< 1.3.0","status":"affected"}]}]}],"metrics":{"cvssMetricV31":[{"source":"security-advisories@github.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H","baseScore":9.6,"baseSeverity":"CRITICAL","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"NONE","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":3.1,"impactScore":5.8}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-04-23T14:15:09.611330Z","id":"CVE-2026-33471","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"weaknesses":[{"source":"security-advisories@github.com","type":"Secondary","description":[{"lang":"en","value":"CWE-20"},{"lang":"en","value":"CWE-190"},{"lang":"en","value":"CWE-345"},{"lang":"en","value":"CWE-1284"}]}],"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:nimiq:nimiq_proof-of-stake:*:*:*:*:*:rust:*:*","versionEndExcluding":"1.3.0","matchCriteriaId":"CD0CAAD1-7626-4A4A-A6F8-9DC46FE50731"}]}]}],"references":[{"url":"https://github.com/nimiq/core-rs-albatross/commit/d02059053181ed8ddad6b59a0adfd661ef5cd823","source":"security-advisories@github.com","tags":["Patch"]},{"url":"https://github.com/nimiq/core-rs-albatross/releases/tag/v1.3.0","source":"security-advisories@github.com","tags":["Release Notes"]},{"url":"https://github.com/nimiq/core-rs-albatross/security/advisories/GHSA-6973-8887-87ff","source":"security-advisories@github.com","tags":["Patch","Vendor Advisory"]}]}