Integer overflow causes an infinite loop in message buffer growth in PgBouncer

{
  "id": "fe7a33f78c51ff371c1372d2455cebc912f55eb9107ff46f59251bbd1a117f8d",
  "url": "https://osv.dev/vulnerability/BIT-pgbouncer-2026-107348",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Integer overflow causes an infinite loop in message buffer growth in PgBouncer",
    "summary": "Integer overflow in the message buffer growth logic (mbuf_make_room) in PgBouncer 1.21.0 through 1.26.0 allows a remote attacker to cause a denial of service when max_packet_size is configured above 2147483648. A packet header declaring a length above 2^31 makes the buffer size computation overflow, leaving the growth loop unable to terminate. Because PgBouncer serves all clients from a single process, this saturates a CPU core and stalls every pooled connection until the process is restarted. Since 1.23.0 the overflow is reachable before authentication with a five-byte packet header.",
    "evidence": "osv:BIT-pgbouncer-2026-107348",
    "products": [
      {
        "name": {
          "value": "pgbouncer",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1.26.1",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "BIT-pgbouncer-2026-107348",
      "aliases": [
        "BIT-pgbouncer-2026-107348",
        "CVE-2026-107348"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "1.21.0"
                },
                {
                  "fixed": "1.26.1"
                }
              ]
            }
          ],
          "package": {
            "name": "pgbouncer",
            "purl": "pkg:bitnami/pgbouncer",
            "ecosystem": "Bitnami"
          },
          "severity": [
            {
              "type": "CVSS_V3",
              "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"
            }
          ],
          "database_specific": {
            "source": "https://github.com/bitnami/vulndb/tree/main/data/pgbouncer/BIT-pgbouncer-2026-107348.json"
          }
        }
      ],
      "modified": "2026-10-21T12:00:37.733771573Z",
      "provider": "osv",
      "references": [
        "https://nvd.nist.gov/vuln/detail/CVE-2026-107348",
        "https://www.pgbouncer.org/changelog.html"
      ],
      "provider_metadata": {
        "cpes": [
          "cpe:2.3:a:pgbouncer:pgbouncer:*:*:*:*:*:*:*:*"
        ],
        "severity": "Medium"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-107348",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/database_specific/severity"
  },
  "source_id": "core-osv",
  "document_id": 393017,
  "published_at": "2026-10-21T08:55:08.744+00:00"
}