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GHSA-W79M-39MQ-X36C

Vulnerability from github – Published: 2026-09-23 18:31 – Updated: 2026-09-23 18:31

Details

Missing validation of a mandatory attribute in the SCRAM client-final-message parser in PgBouncer through 1.25.2 allows an unauthenticated remote attacker to crash the process. A malformed message can make the parser report success while leaving a required value unset, which is then dereferenced as a NULL pointer. The crash occurs before any credential is verified, so no valid account is required. Because PgBouncer serves all clients from a single process, this terminates every pooled connection.

Severity

7.5 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2026-19888"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-476"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-23T17:17:14Z",
    "severity": "HIGH"
  },
  "details": "Missing validation of a mandatory attribute in the SCRAM client-final-message parser in PgBouncer through 1.25.2 allows an unauthenticated remote attacker to crash the process. A malformed message can make the parser report success while leaving a required value unset, which is then dereferenced as a NULL pointer. The crash occurs before any credential is verified, so no valid account is required. Because PgBouncer serves all clients from a single process, this terminates every pooled connection.",
  "id": "GHSA-w79m-39mq-x36c",
  "modified": "2026-09-23T18:31:56Z",
  "published": "2026-09-23T18:31:56Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-19888"
    },
    {
      "type": "WEB",
      "url": "https://www.pgbouncer.org/changelog.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-19888 (GCVE-0-2026-19888)

Vulnerability from cvelistv5 – Published: 2026-09-23 16:04 – Updated: 2026-09-23 16:46

Title

NULL pointer dereference in SCRAM client-final-message parsing in PgBouncer

Summary

Severity

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-23 16:33 UTC

CWE

CWE-476 - NULL Pointer Dereference

Assigner

PostgreSQL redhat root

References

1 reference

URL	Tags
https://www.pgbouncer.org/changelog.html

Impacted products

1 product

Vendor	Product	Version
n/a	PgBouncer	Affected: 0 , ≤ 1.25.2 (semver)

Credits

Thanks to @mble for finding and reporting this issue. Independently reported by @thesecguy45. Independently reported by @umutbasal. Independently reported by @jackds-security. Independently reported by @palak-paneer. Independently reported by @shakirov-vm.

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-19888",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-09-23T16:33:38.167752Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-09-23T16:46:13.585Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "PgBouncer",
          "vendor": "n/a",
          "versions": [
            {
              "lessThanOrEqual": "1.25.2",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "configurations": [
        {
          "lang": "en",
          "value": "auth_type is set to scram-sha-256 (non-default configuration), or auth_type is set to md5 (default configuration) and a user has a SCRAM secret stored, which causes PgBouncer to upgrade that login to SCRAM"
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Thanks to @mble for finding and reporting this issue."
        },
        {
          "lang": "en",
          "type": "finder",
          "value": "Independently reported by @thesecguy45."
        },
        {
          "lang": "en",
          "type": "finder",
          "value": "Independently reported by @umutbasal."
        },
        {
          "lang": "en",
          "type": "finder",
          "value": "Independently reported by @jackds-security."
        },
        {
          "lang": "en",
          "type": "finder",
          "value": "Independently reported by @palak-paneer."
        },
        {
          "lang": "en",
          "type": "finder",
          "value": "Independently reported by @shakirov-vm."
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Missing validation of a mandatory attribute in the SCRAM client-final-message parser in PgBouncer through 1.25.2 allows an unauthenticated remote attacker to crash the process. A malformed message can make the parser report success while leaving a required value unset, which is then dereferenced as a NULL pointer. The crash occurs before any credential is verified, so no valid account is required. Because PgBouncer serves all clients from a single process, this terminates every pooled connection."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "format": "CVSS"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-476",
              "description": "NULL Pointer Dereference",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-23T16:04:48.392Z",
        "orgId": "f86ef6dc-4d3a-42ad-8f28-e6d5547a5007",
        "shortName": "PostgreSQL"
      },
      "references": [
        {
          "url": "https://www.pgbouncer.org/changelog.html"
        }
      ],
      "title": "NULL pointer dereference in SCRAM client-final-message parsing in PgBouncer",
      "workarounds": [
        {
          "lang": "en",
          "value": "Restrict network access to the PgBouncer listener to trusted clients. No configuration change avoids the issue for deployments that must accept SCRAM authentication from untrusted networks, because the crash occurs before any credential is verified and PgBouncer performs a mock SCRAM exchange even for users that do not exist."
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "f86ef6dc-4d3a-42ad-8f28-e6d5547a5007",
    "assignerShortName": "PostgreSQL",
    "cveId": "CVE-2026-19888",
    "datePublished": "2026-09-23T16:04:48.392Z",
    "dateReserved": "2026-08-14T16:55:37.365Z",
    "dateUpdated": "2026-09-23T16:46:13.585Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
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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.

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GHSA-W79M-39MQ-X36C

CVE-2026-19888 (GCVE-0-2026-19888)

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