Klever-Go: PubKeysBitmap padding bits bypass the BLS signature quorum

{
  "id": "a0cf7a12cd2ed8e06789cb38b9a4c773deae0706f432c3e6a47ce20a270f448e",
  "url": "https://osv.dev/vulnerability/CVE-2026-58262",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Klever-Go: PubKeysBitmap padding bits bypass the BLS signature quorum",
    "summary": "Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.20, header signature verification counts the unused padding bits of the PubKeysBitmap toward the two-thirds validator quorum. These padding bits do not correspond to any validator and are ignored by the actual BLS aggregate-signature check, so a malicious or compromised block producer can set them to reach the required quorum while gathering fewer genuine validator signatures than the protocol demands. As a result, nodes that import or intercept the header accept it as correctly signed without a real two-thirds quorum, weakening consensus safety and undermining finality. This issue is fixed in version 1.7.20.",
    "evidence": "osv:CVE-2026-58262",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-58262",
      "aliases": [
        "CVE-2026-58262",
        "GHSA-f9h7-4mmq-vgcq"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/klever-io/klever-go",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "0b70b0f1a1f5d95ac07c2038c227db7f18976a2a"
                },
                {
                  "fixed": "a11cb28e495e608d8034dbe83a91e89d0c68e0f7"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "1.7.20"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "a11cb28e495e608d8034dbe83a91e89d0c68e0f7"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v1.7.19",
            "v1.7.18",
            "v1.7.17",
            "v1.7.16",
            "v1.7.15",
            "v1.7.14"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-58262.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:40.312092237Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/58xxx/CVE-2026-58262.json",
        "https://github.com/klever-io/klever-go/security/advisories/GHSA-f9h7-4mmq-vgcq",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-58262",
        "https://github.com/klever-io/klever-go/commit/a11cb28e495e608d8034dbe83a91e89d0c68e0f7"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-345",
          "CWE-347"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/58xxx/CVE-2026-58262.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-58262",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 508122,
  "published_at": "2026-08-07T22:00:57.154+00:00"
}