PyQuorum: Timing side‑channel in mul_mod

{
  "id": "c262d6bdef11391f1bae968a06915b5a95cf0336bd4b033c4a0643cc41e62dc5",
  "url": "https://osv.dev/vulnerability/CVE-2026-44368",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "PyQuorum: Timing side‑channel in mul_mod",
    "summary": "PyQuorum is a cryptographic library for secret sharing and key management. Prior to 0.2.1, the mul_mod function implements multiplication via a binary expansion loop whose execution time depends on the Hamming weight of the second operand (the exponent). An attacker who can measure the time of secret‑sharing operations (e.g., via a remote service) could progressively recover the values of shares, ultimately leading to secret reconstruction. This vulnerability is fixed in 0.2.1.",
    "evidence": "osv:CVE-2026-44368",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-44368",
      "aliases": [
        "CVE-2026-44368",
        "GHSA-7r92-3jgr-r65q",
        "PYSEC-2026-3028"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/svvqt/pyquorum",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "fde2aa02ea1f4a66dd42aa6b59a6071335d1e8c3"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "0.2.1"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "0.2.1"
                      }
                    ],
                    "source": "DESCRIPTION"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v0.2.0",
            "v0.1.3",
            "v0.1.2"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-44368.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:41.547296233Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44368.json",
        "https://github.com/svvqt/pyquorum/security/advisories/GHSA-7r92-3jgr-r65q",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-44368"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-208"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44368.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-44368",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 509029,
  "published_at": "2026-05-13T20:18:12.91+00:00"
}