When writing data larger than 4GB in a single Write call on an SSH channel, an integer overflow in the internal payload size calculation caused the write loop to spin indefinitely, sending empty pa...

{
  "id": "1e33d499f28f0a92033ba5d9ec71ca0cd8708b9e18fe3dc8fe67171d4007302b",
  "url": "https://osv.dev/vulnerability/CLEANSTART-2026-OL23592",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "When writing data larger than 4GB in a single Write call on an SSH channel, an integer overflow in the internal payload size calculation caused the write loop to spin indefinitely, sending empty pa...",
    "summary": "CVE-2026-39834 affects multiple packages. When writing data larger than 4GB in a single Write call on an SSH channel, an integer overflow in the internal payload size calculation caused the write loop to spin indefinitely, sending empty packets without making progress. See references for individual vulnerability details.",
    "evidence": "osv:CLEANSTART-2026-OL23592",
    "products": [
      {
        "name": {
          "value": "external-dns",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "0.20.0-r2",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "temporal-server-fips",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1.32.0-r2",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "vault",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1.19.5-r6",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "critical",
    "structured": {
      "id": "CLEANSTART-2026-OL23592",
      "aliases": [
        "CLEANSTART-2026-OL23592"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "0.20.0-r2"
                }
              ]
            }
          ],
          "package": {
            "name": "external-dns",
            "purl": "pkg:apk/cleanstart/external-dns",
            "ecosystem": "CleanStart"
          },
          "database_specific": {
            "source": "https://github.com/cleanstart-dev/cleanstart-security-advisories/blob/main/advisories/2026/CLEANSTART-2026-OL23592.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1.32.0-r2"
                }
              ]
            }
          ],
          "package": {
            "name": "temporal-server-fips",
            "purl": "pkg:apk/cleanstart/temporal-server-fips",
            "ecosystem": "CleanStart"
          },
          "database_specific": {
            "source": "https://github.com/cleanstart-dev/cleanstart-security-advisories/blob/main/advisories/2026/CLEANSTART-2026-OL23592.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1.19.5-r6"
                }
              ]
            }
          ],
          "package": {
            "name": "vault",
            "purl": "pkg:apk/cleanstart/vault",
            "ecosystem": "CleanStart"
          },
          "database_specific": {
            "source": "https://github.com/cleanstart-dev/cleanstart-security-advisories/blob/main/advisories/2026/CLEANSTART-2026-OL23592.json"
          }
        }
      ],
      "modified": "2026-10-08T16:47:11.547782530Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-39834"
      ],
      "references": [
        "https://github.com/cleanstart-dev/cleanstart-security-advisories/tree/main/advisories/2026/CLEANSTART-2026-OL23592.json",
        "https://osv.dev/vulnerability/CVE-2026-39834",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-39834"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2026-39834",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 102058,
  "published_at": "2026-10-08T00:37:21.335+00:00"
}