Vulnerability-Lookup

ubuntu-cve-2026-18691

Vulnerability from osv_ubuntu

Published

2026-08-11 19:17

Modified

2026-08-19 11:01

Summary

Details

An issue in MongoDB Server's intra-cluster connection setup could allow a party with suitable network access to influence which authentication mechanism is used when one replica set member connects to another. Under certain conditions, this could cause the cluster's shared internal credential to be transmitted in a less-protected form, potentially allowing that credential to be recovered. If recovered, the credential could be used to authenticate as the internal superuser to nodes in the deployment.

Severity

8.8 (High)


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

9.0 (Critical)


                    
                      CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-18691	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-18691	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "mongodb",
            "binary_version": "1:2.4.9-1ubuntu2+esm2"
          },
          {
            "binary_name": "mongodb-clients",
            "binary_version": "1:2.4.9-1ubuntu2+esm2"
          },
          {
            "binary_name": "mongodb-server",
            "binary_version": "1:2.4.9-1ubuntu2+esm2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:14.04:LTS",
        "name": "mongodb",
        "purl": "pkg:deb/ubuntu/mongodb@1:2.4.9-1ubuntu2+esm2?arch=source\u0026distro=esm-infra-legacy/trusty"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:2.4.6-0ubuntu5",
        "1:2.4.6-0ubuntu6",
        "1:2.4.8-1ubuntu1",
        "1:2.4.8-2",
        "1:2.4.9-1",
        "1:2.4.9-1ubuntu1",
        "1:2.4.9-1ubuntu2",
        "1:2.4.9-1ubuntu2+esm2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "mongodb",
            "binary_version": "1:2.6.10-0ubuntu1+esm2"
          },
          {
            "binary_name": "mongodb-clients",
            "binary_version": "1:2.6.10-0ubuntu1+esm2"
          },
          {
            "binary_name": "mongodb-server",
            "binary_version": "1:2.6.10-0ubuntu1+esm2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "mongodb",
        "purl": "pkg:deb/ubuntu/mongodb@1:2.6.10-0ubuntu1+esm2?arch=source\u0026distro=esm-apps/xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:2.6.10-0ubuntu1",
        "1:2.6.10-0ubuntu1+esm2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "mongodb",
            "binary_version": "1:3.6.3-0ubuntu1.4+esm2"
          },
          {
            "binary_name": "mongodb-clients",
            "binary_version": "1:3.6.3-0ubuntu1.4+esm2"
          },
          {
            "binary_name": "mongodb-server",
            "binary_version": "1:3.6.3-0ubuntu1.4+esm2"
          },
          {
            "binary_name": "mongodb-server-core",
            "binary_version": "1:3.6.3-0ubuntu1.4+esm2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "mongodb",
        "purl": "pkg:deb/ubuntu/mongodb@1:3.6.3-0ubuntu1.4+esm2?arch=source\u0026distro=esm-apps/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:3.4.7-1",
        "1:3.4.7-1ubuntu1",
        "1:3.4.7-1ubuntu2",
        "1:3.4.7-1ubuntu4",
        "1:3.4.14-3ubuntu1",
        "1:3.4.14-3ubuntu2",
        "1:3.6.3-0ubuntu1",
        "1:3.6.3-0ubuntu1.1",
        "1:3.6.3-0ubuntu1.3",
        "1:3.6.3-0ubuntu1.4",
        "1:3.6.3-0ubuntu1.4+esm1",
        "1:3.6.3-0ubuntu1.4+esm2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "mongodb",
            "binary_version": "1:3.6.9+really3.6.8+90~g8e540c0b6d-0ubuntu5.3+esm1"
          },
          {
            "binary_name": "mongodb-clients",
            "binary_version": "1:3.6.9+really3.6.8+90~g8e540c0b6d-0ubuntu5.3+esm1"
          },
          {
            "binary_name": "mongodb-server",
            "binary_version": "1:3.6.9+really3.6.8+90~g8e540c0b6d-0ubuntu5.3+esm1"
          },
          {
            "binary_name": "mongodb-server-core",
            "binary_version": "1:3.6.9+really3.6.8+90~g8e540c0b6d-0ubuntu5.3+esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "mongodb",
        "purl": "pkg:deb/ubuntu/mongodb@1:3.6.9+really3.6.8+90~g8e540c0b6d-0ubuntu5.3+esm1?arch=source\u0026distro=esm-apps/focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:3.6.9+really3.6.8+90~g8e540c0b6d-0ubuntu2",
        "1:3.6.9+really3.6.8+90~g8e540c0b6d-0ubuntu5",
        "1:3.6.9+really3.6.8+90~g8e540c0b6d-0ubuntu5.2",
        "1:3.6.9+really3.6.8+90~g8e540c0b6d-0ubuntu5.3",
        "1:3.6.9+really3.6.8+90~g8e540c0b6d-0ubuntu5.3+esm1"
      ]
    }
  ],
  "aliases": [],
  "details": "An issue in MongoDB Server\u0027s intra-cluster connection setup could allow a party with suitable network access to influence which authentication mechanism is used when one replica set member connects to another. Under certain conditions, this could cause the cluster\u0027s shared internal credential to be transmitted in a less-protected form, potentially allowing that credential to be recovered. If recovered, the credential could be used to authenticate as the internal superuser to nodes in the deployment.",
  "id": "UBUNTU-CVE-2026-18691",
  "modified": "2026-08-19T11:01:27Z",
  "published": "2026-08-11T19:17:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-18691"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-18691"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H",
      "type": "CVSS_V4"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-18691"
  ]
}

CVE-2026-18691 (GCVE-0-2026-18691)

Vulnerability from cvelistv5 – Published: 2026-08-11 18:46 – Updated: 2026-08-11 20:22

Title

Improper Authentication in MongoDB Intra-Cluster Connections Allows Credential Exposure

Summary

Severity

9 (Critical)


                        
                          CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

8.8 (High)


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

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-11 20:21 UTC

CWE

CWE-757 - Selection of Less-Secure Algorithm During Negotiation ('Algorithm Downgrade')

Assigner

mongodb mitre root

References

1 reference

URL	Tags
https://jira.mongodb.org/browse/SERVER-130264

Impacted products

1 product

Vendor	Product	Version
MongoDB	MongoDB Server	Affected: 8.3.0 , < 8.3.8 (semver) Affected: 8.0 , < 8.0.29 (semver) Affected: 7.0 , < 7.0.40 (semver)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-18691",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-11T20:21:49.480663Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-08-11T20:22:00.933Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "MongoDB Server",
          "vendor": "MongoDB",
          "versions": [
            {
              "lessThan": "8.3.8",
              "status": "affected",
              "version": "8.3.0",
              "versionType": "semver"
            },
            {
              "lessThan": "8.0.29",
              "status": "affected",
              "version": "8.0",
              "versionType": "semver"
            },
            {
              "lessThan": "7.0.40",
              "status": "affected",
              "version": "7.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
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              "base64": false,
              "type": "text/html",
              "value": "An issue in MongoDB Server\u0027s intra-cluster connection setup could allow a party with suitable network access to influence which authentication mechanism is used when one replica set member connects to another. Under certain conditions, this could cause the cluster\u0027s shared internal credential to be transmitted in a less-protected form, potentially allowing that credential to be recovered. If recovered, the credential could be used to authenticate as the internal superuser to nodes in the deployment."
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        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "ADJACENT",
            "baseScore": 9,
            "baseSeverity": "CRITICAL",
            "exploitMaturity": "NOT_DEFINED",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "HIGH",
            "subConfidentialityImpact": "HIGH",
            "subIntegrityImpact": "HIGH",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H",
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            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "exploitCodeMaturity": "NOT_DEFINED",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "remediationLevel": "NOT_DEFINED",
            "reportConfidence": "NOT_DEFINED",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
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      "problemTypes": [
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          "descriptions": [
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      "references": [
        {
          "url": "https://jira.mongodb.org/browse/SERVER-130264"
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    "dateReserved": "2026-08-03T15:53:04.081Z",
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}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
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.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.