CVE-2026-33471 (GCVE-0-2026-33471)

Vulnerability from cvelistv5 – Published: 2026-04-22 19:13 – Updated: 2026-04-23 14:15
VLAI?
Title
nimiq-block has skip block quorum bypass via out-of-range BitSet indices & u16 truncation
Summary
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.
Severity ?
9.6 (Critical)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H
CWE
  • CWE-20 - Improper Input Validation
  • CWE-190 - Integer Overflow or Wraparound
  • CWE-345 - Insufficient Verification of Data Authenticity
  • CWE-1284 - Improper Validation of Specified Quantity in Input
Assigner
References
Impacted products
Vendor Product Version
nimiq nimiq-block Affected: < 1.3.0
Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-33471",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-04-23T14:15:09.611330Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-04-23T14:15:20.570Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "nimiq-block",
          "vendor": "nimiq",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 1.3.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "nimiq-block contains block primitives to be used in Nimiq\u0027s 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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 9.6,
            "baseSeverity": "CRITICAL",
            "confidentialityImpact": "NONE",
            "integrityImpact": "HIGH",
            "privilegesRequired": "LOW",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-20",
              "description": "CWE-20: Improper Input Validation",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-190",
              "description": "CWE-190: Integer Overflow or Wraparound",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-345",
              "description": "CWE-345: Insufficient Verification of Data Authenticity",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-1284",
              "description": "CWE-1284: Improper Validation of Specified Quantity in Input",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-22T19:45:53.754Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/nimiq/core-rs-albatross/security/advisories/GHSA-6973-8887-87ff",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/nimiq/core-rs-albatross/security/advisories/GHSA-6973-8887-87ff"
        },
        {
          "name": "https://github.com/nimiq/core-rs-albatross/commit/d02059053181ed8ddad6b59a0adfd661ef5cd823",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/nimiq/core-rs-albatross/commit/d02059053181ed8ddad6b59a0adfd661ef5cd823"
        },
        {
          "name": "https://github.com/nimiq/core-rs-albatross/releases/tag/v1.3.0",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/nimiq/core-rs-albatross/releases/tag/v1.3.0"
        }
      ],
      "source": {
        "advisory": "GHSA-6973-8887-87ff",
        "discovery": "UNKNOWN"
      },
      "title": "nimiq-block has skip block quorum bypass via out-of-range BitSet indices \u0026 u16 truncation"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-33471",
    "datePublished": "2026-04-22T19:13:04.687Z",
    "dateReserved": "2026-03-20T16:16:48.969Z",
    "dateUpdated": "2026-04-23T14:15:20.570Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-33471",
      "date": "2026-04-23",
      "epss": "0.00025",
      "percentile": "0.07005"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-33471\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-04-22T20:16:40.317\",\"lastModified\":\"2026-04-22T21:23:52.620\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"nimiq-block contains block primitives to be used in Nimiq\u0027s 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.\"}],\"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}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-20\"},{\"lang\":\"en\",\"value\":\"CWE-190\"},{\"lang\":\"en\",\"value\":\"CWE-345\"},{\"lang\":\"en\",\"value\":\"CWE-1284\"}]}],\"references\":[{\"url\":\"https://github.com/nimiq/core-rs-albatross/commit/d02059053181ed8ddad6b59a0adfd661ef5cd823\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/nimiq/core-rs-albatross/releases/tag/v1.3.0\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/nimiq/core-rs-albatross/security/advisories/GHSA-6973-8887-87ff\",\"source\":\"security-advisories@github.com\"}]}}",
    "vulnrichment": {
      "containers": "{\"cna\": {\"title\": \"nimiq-block has skip block quorum bypass via out-of-range BitSet indices \u0026 u16 truncation\", \"problemTypes\": [{\"descriptions\": [{\"cweId\": \"CWE-20\", \"lang\": \"en\", \"description\": \"CWE-20: Improper Input Validation\", \"type\": \"CWE\"}]}, {\"descriptions\": [{\"cweId\": \"CWE-190\", \"lang\": \"en\", \"description\": \"CWE-190: Integer Overflow or Wraparound\", \"type\": \"CWE\"}]}, {\"descriptions\": [{\"cweId\": \"CWE-345\", \"lang\": \"en\", \"description\": \"CWE-345: Insufficient Verification of Data Authenticity\", \"type\": \"CWE\"}]}, {\"descriptions\": [{\"cweId\": \"CWE-1284\", \"lang\": \"en\", \"description\": \"CWE-1284: Improper Validation of Specified Quantity in Input\", \"type\": \"CWE\"}]}], \"metrics\": [{\"cvssV3_1\": {\"attackComplexity\": \"LOW\", \"attackVector\": \"NETWORK\", \"availabilityImpact\": \"HIGH\", \"baseScore\": 9.6, \"baseSeverity\": \"CRITICAL\", \"confidentialityImpact\": \"NONE\", \"integrityImpact\": \"HIGH\", \"privilegesRequired\": \"LOW\", \"scope\": \"CHANGED\", \"userInteraction\": \"NONE\", \"vectorString\": \"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H\", \"version\": \"3.1\"}}], \"references\": [{\"name\": \"https://github.com/nimiq/core-rs-albatross/security/advisories/GHSA-6973-8887-87ff\", \"tags\": [\"x_refsource_CONFIRM\"], \"url\": \"https://github.com/nimiq/core-rs-albatross/security/advisories/GHSA-6973-8887-87ff\"}, {\"name\": \"https://github.com/nimiq/core-rs-albatross/commit/d02059053181ed8ddad6b59a0adfd661ef5cd823\", \"tags\": [\"x_refsource_MISC\"], \"url\": \"https://github.com/nimiq/core-rs-albatross/commit/d02059053181ed8ddad6b59a0adfd661ef5cd823\"}, {\"name\": \"https://github.com/nimiq/core-rs-albatross/releases/tag/v1.3.0\", \"tags\": [\"x_refsource_MISC\"], \"url\": \"https://github.com/nimiq/core-rs-albatross/releases/tag/v1.3.0\"}], \"affected\": [{\"vendor\": \"nimiq\", \"product\": \"nimiq-block\", \"versions\": [{\"version\": \"\u003c 1.3.0\", \"status\": \"affected\"}]}], \"providerMetadata\": {\"orgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"shortName\": \"GitHub_M\", \"dateUpdated\": \"2026-04-22T19:45:53.754Z\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"nimiq-block contains block primitives to be used in Nimiq\u0027s 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.\"}], \"source\": {\"advisory\": \"GHSA-6973-8887-87ff\", \"discovery\": \"UNKNOWN\"}}, \"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-33471\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-04-23T14:15:09.611330Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-04-23T14:15:16.296Z\"}}]}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-33471\", \"assignerOrgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"state\": \"PUBLISHED\", \"assignerShortName\": \"GitHub_M\", \"dateReserved\": \"2026-03-20T16:16:48.969Z\", \"datePublished\": \"2026-04-22T19:13:04.687Z\", \"dateUpdated\": \"2026-04-23T14:15:20.570Z\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.