Vulnerability-Lookup

CVE-2026-55856 (GCVE-0-2026-55856)

Vulnerability from cvelistv5 – Published: 2026-08-28 22:41 – Updated: 2026-08-31 18:37

Title

MariaDB Connector/J: Cleartext password disclosure to a MITM on the initial-handshake

Summary

MariaDB Connector/J is used to connect applications developed in Java to MariaDB and MySQL databases. Prior to 2.7.14, 3.3.5, 3.4.3, and 3.5.9, when a Java application connects with sslMode=verify-full or sslMode=verify-ca, supplies a password, and does not configure serverSslCert or trustStore, Connector/J can accept an untrusted self-signed certificate through the fallbackToSystemTrustStore=true ephemeral trust manager and record its certFingerprint for later identity binding. The OK-packet and authentication-switch paths enforce the certificate fingerprint, but the initial-handshake path does not. HandshakeResponse.encode() can therefore build and send a mysql_clear_password response before checking certFingerprint != null && !isMitMProof(), sslMode, or whether the authentication plugin is resistant to a man-in-the-middle, and the initial path also bypasses restrictedAuth. An active man-in-the-middle or hostile server can present a self-signed certificate, claim to be MariaDB, select mysql_clear_password as the initial authentication plugin, and receive the full database password before the connection is rejected. This issue is fixed in versions 2.7.14, 3.3.5, 3.4.3, and 3.5.9.

Severity

5.9 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-31 18:37 UTC

CWE

CWE-522 - Insufficiently Protected Credentials

Assigner

GitHub_M mitre root

References

7 references

URL	Tags
https://github.com/mariadb-corporation/mariadb-co…	x_refsource_CONFIRM
https://github.com/mariadb-corporation/mariadb-co…	x_refsource_MISC
https://github.com/mariadb-corporation/mariadb-co…	x_refsource_MISC
https://hackerone.com/reports/3777370	x_refsource_MISC
https://github.com/mariadb-corporation/mariadb-co…	x_refsource_MISC
https://github.com/mariadb-corporation/mariadb-co…	x_refsource_MISC
https://jira.mariadb.org/browse/CONJ-1325	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version	CPE status
mariadb-corporation	mariadb-connector-j	Affected: < 2.7.14 Affected: >= 3.0.0, < 3.3.5 Affected: >= 3.4.0, < 3.4.3 Affected: >= 3.5.0, < 3.5.9	guessed

Show details on NVD website

JSON

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}

CLEANSTART-2026-MO09576 (CVE-2026-55856)

Vulnerability from cleanstart – Published: 2026-09-18 09:31 – Updated: 2026-08-31 12:14 – Source website

Summary

Security fix for CVE-2026-55856 applied in: keycloak 26.5.7-r8

Details

Security vulnerability affects the keycloak package. This issue is resolved in later releases. See references for vulnerability details.

References

URL

Type

	https://github.com/cleanstart-dev/cleanstart-secu…	ADVISORY
	https://osv.dev/vulnerability/CVE-2026-55856	WEB
	https://nvd.nist.gov/vuln/detail/CVE-2026-55856	WEB

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "CleanStart",
        "name": "keycloak"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "26.5.7-r8"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "credits": [],
  "database_specific": {},
  "details": "Security vulnerability affects the keycloak package. This issue is resolved in later releases. See references for vulnerability details.",
  "id": "CLEANSTART-2026-MO09576",
  "modified": "2026-08-31T12:14:47Z",
  "published": "2026-09-18T09:31:02.807235Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/cleanstart-dev/cleanstart-security-advisories/tree/main/advisories/2026/CLEANSTART-2026-MO09576.json"
    },
    {
      "type": "WEB",
      "url": "https://osv.dev/vulnerability/CVE-2026-55856"
    },
    {
      "type": "WEB",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-55856"
    }
  ],
  "related": [],
  "schema_version": "1.7.3",
  "summary": "Security fix for CVE-2026-55856 applied in: keycloak 26.5.7-r8",
  "upstream": [
    "CVE-2026-55856"
  ]
}

FKIE_CVE-2026-55856

Vulnerability from fkie_nvd - Published: 2026-08-28 23:17 - Updated: 2026-09-08 21:08

Severity

5.9 (Medium) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/mariadb-corporation/mariadb-connector-j/commit/149ec6a626376214966c01f42d48be1b80d06056
	security-advisories@github.com	https://github.com/mariadb-corporation/mariadb-connector-j/commit/d90b9872322c76b05a48219be66bff1d33102f8a
	security-advisories@github.com	https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.4.3
	security-advisories@github.com	https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.5.9
	security-advisories@github.com	https://github.com/mariadb-corporation/mariadb-connector-j/security/advisories/GHSA-g9jj-cgmh-9f38
	security-advisories@github.com	https://hackerone.com/reports/3777370
	security-advisories@github.com	https://jira.mariadb.org/browse/CONJ-1325

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "mariadb-connector-j",
          "vendor": "mariadb-corporation",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 2.7.14"
            },
            {
              "status": "affected",
              "version": "\u003e= 3.0.0, \u003c 3.3.5"
            },
            {
              "status": "affected",
              "version": "\u003e= 3.4.0, \u003c 3.4.3"
            },
            {
              "status": "affected",
              "version": "\u003e= 3.5.0, \u003c 3.5.9"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "MariaDB Connector/J is used to connect applications developed in Java to MariaDB and MySQL databases. Prior to 2.7.14, 3.3.5, 3.4.3, and 3.5.9, when a Java application connects with sslMode=verify-full or sslMode=verify-ca, supplies a password, and does not configure serverSslCert or trustStore, Connector/J can accept an untrusted self-signed certificate through the fallbackToSystemTrustStore=true ephemeral trust manager and record its certFingerprint for later identity binding. The OK-packet and authentication-switch paths enforce the certificate fingerprint, but the initial-handshake path does not. HandshakeResponse.encode() can therefore build and send a mysql_clear_password response before checking certFingerprint != null \u0026\u0026 !isMitMProof(), sslMode, or whether the authentication plugin is resistant to a man-in-the-middle, and the initial path also bypasses restrictedAuth. An active man-in-the-middle or hostile server can present a self-signed certificate, claim to be MariaDB, select mysql_clear_password as the initial authentication plugin, and receive the full database password before the connection is rejected. This issue is fixed in versions 2.7.14, 3.3.5, 3.4.3, and 3.5.9."
    }
  ],
  "id": "CVE-2026-55856",
  "lastModified": "2026-09-08T21:08:37.320",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 5.9,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.2,
        "impactScore": 3.6,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-55856",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-08-31T18:37:25.396891Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-28T23:17:08.513",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/mariadb-corporation/mariadb-connector-j/commit/149ec6a626376214966c01f42d48be1b80d06056"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/mariadb-corporation/mariadb-connector-j/commit/d90b9872322c76b05a48219be66bff1d33102f8a"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.4.3"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.5.9"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/mariadb-corporation/mariadb-connector-j/security/advisories/GHSA-g9jj-cgmh-9f38"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://hackerone.com/reports/3777370"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://jira.mariadb.org/browse/CONJ-1325"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-522"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}

GHSA-G9JJ-CGMH-9F38

Vulnerability from github – Published: 2026-08-28 22:41 – Updated: 2026-08-28 22:41

Summary

MariaDB has cleartext password disclosure to a MITM on the initial-handshake

Details

Summary

When a Java application connects with sslMode=verify-full (or verify-ca) and a password but does not pin a server certificate, Connector/J deliberately accepts an untrusted/self-signed certificate at the TLS layer (the "MITM-proof without a CA" feature) and proves the server's identity afterwards by binding the certificate fingerprint into the authentication exchange. That fingerprint enforcement is applied to the OK-packet and auth-switch paths but not to the initial-handshake path. An active man-in-the-middle that presents a self-signed certificate, claims to be MariaDB, and names the initial authentication plugin mysql_clear_password receives the victim's database password in cleartext, before any fingerprint/identity check runs. The connection is torn down a moment later, but the credential is already gone.

Details

For sslMode=verify-full/verify-ca with a password and no serverSslCert/trustStore, the connector falls back to an ephemeral trust manager (default fallbackToSystemTrustStore=true) that accepts any non-expired certificate at the TLS layer and records its fingerprint. Identity is then meant to be enforced via that fingerprint.

The enforcement guard is present on two of the three paths, the OK-packet fingerprint check and the auth-switch handler (where the clear-password plugin is only allowed when the fingerprint is already verified). It is absent on the initial-handshake send: HandshakeResponse.encode() builds the mysql_clear_password response after checking only that SSL is enabled, never consulting the recorded fingerprint, sslMode, or whether the plugin is MITM-proof. By that point the connector already knows the certificate was self-signed. The clear-password plugin does not declare itself MITM-proof (it inherits the safe default), which confirms it is meant to be refused on an unverified certificate; the initial-handshake path simply never consults that flag. The initial path also bypasses restrictedAuth.

Impact

An active man-in-the-middle steals the full cleartext database password of any Java application using Connector/J with sslMode=verify-full/verify-ca plus a password and no pinned certificate, the configuration documented as the easy, secure default. With the captured credentials the attacker can take over the database account and read or modify all data that account is authorized for. The victim takes no unusual action; the developer explicitly enabled TLS verification expecting exactly this protection.

Patches

Fixed in 2.7.14, 3.3.5, 3.4.3, and 3.5.9. Upgrade to the patched release on your branch (3.5.x → 3.5.9, 3.4.x → 3.4.3, 3.0/3.1/3.2/3.3.x → 3.3.5, 2.x → 2.7.14). The fix applies the same certFingerprint != null && !isMitMProof() guard to the initial-handshake path before writing the auth response, refusing to send a mysql_clear_password (or any non-MITM-proof) response on an as-yet-unverified certificate, matching the auth-switch path.

Workarounds

If you cannot upgrade immediately, pin the server certificate (serverSslCert= the real CA / server cert). With a pinned certificate the self-signed certificate of a man-in-the-middle is rejected at the TLS layer before any password is transmitted.

Credit

Reported by haaahaaahiihiiii

Severity

5.9 (Medium)


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

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "Maven",
        "name": "org.mariadb.jdbc:mariadb-java-client"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.7.14"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Maven",
        "name": "org.mariadb.jdbc:mariadb-java-client"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.0.0"
            },
            {
              "fixed": "3.3.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Maven",
        "name": "org.mariadb.jdbc:mariadb-java-client"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.4.0"
            },
            {
              "fixed": "3.4.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Maven",
        "name": "org.mariadb.jdbc:mariadb-java-client"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.5.0"
            },
            {
              "fixed": "3.5.9"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-55856"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-522"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-08-28T22:41:56Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Summary\n\nWhen a Java application connects with sslMode=verify-full (or verify-ca) and a password but does not pin a server certificate, Connector/J deliberately accepts an untrusted/self-signed certificate at the TLS layer (the \"MITM-proof without a CA\" feature) and proves the server\u0027s identity afterwards by binding the certificate fingerprint into the authentication exchange. That fingerprint enforcement is applied to the OK-packet and auth-switch paths but not to the initial-handshake path. An active man-in-the-middle that presents a self-signed certificate, claims to be MariaDB, and names the initial authentication plugin mysql_clear_password receives the victim\u0027s database password in cleartext, before any fingerprint/identity check runs. The connection is torn down a moment later, but the credential is already gone.\n\n### Details\n\nFor sslMode=verify-full/verify-ca with a password and no serverSslCert/trustStore, the connector falls back to an ephemeral trust manager (default fallbackToSystemTrustStore=true) that accepts any non-expired certificate at the TLS layer and records its fingerprint. Identity is then meant to be enforced via that fingerprint.\n\nThe enforcement guard is present on two of the three paths, the OK-packet fingerprint check and the auth-switch handler (where the clear-password plugin is only allowed when the fingerprint is already verified). It is absent on the initial-handshake send: HandshakeResponse.encode() builds the mysql_clear_password response after checking only that SSL is enabled, never consulting the recorded fingerprint, sslMode, or whether the plugin is MITM-proof. By that point the connector already knows the certificate was self-signed. The clear-password plugin does not declare itself MITM-proof (it inherits the safe default), which confirms it is meant to be refused on an unverified certificate; the initial-handshake path simply never consults that flag. The initial path also bypasses restrictedAuth.\n\n### Impact\n\nAn active man-in-the-middle steals the full cleartext database password of any Java application using Connector/J with sslMode=verify-full/verify-ca plus a password and no pinned certificate, the configuration documented as the easy, secure default. With the captured credentials the attacker can take over the database account and read or modify all data that account is authorized for. The victim takes no unusual action; the developer explicitly enabled TLS verification expecting exactly this protection.\n\n### Patches\n\nFixed in 2.7.14, 3.3.5, 3.4.3, and 3.5.9. Upgrade to the patched release on your branch (3.5.x \u2192 3.5.9, 3.4.x \u2192 3.4.3, 3.0/3.1/3.2/3.3.x \u2192 3.3.5, 2.x \u2192 2.7.14). The fix applies the same certFingerprint != null \u0026\u0026 !isMitMProof() guard to the initial-handshake path before writing the auth response, refusing to send a mysql_clear_password (or any non-MITM-proof) response on an as-yet-unverified certificate, matching the auth-switch path.\n\n### Workarounds\n\nIf you cannot upgrade immediately, pin the server certificate (serverSslCert= the real CA / server cert). With a pinned certificate the self-signed certificate of a man-in-the-middle is rejected at the TLS layer before any password is transmitted.\n\nCredit\n\nReported by haaahaaahiihiiii",
  "id": "GHSA-g9jj-cgmh-9f38",
  "modified": "2026-08-28T22:41:56Z",
  "published": "2026-08-28T22:41:56Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/mariadb-corporation/mariadb-connector-j/security/advisories/GHSA-g9jj-cgmh-9f38"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mariadb-corporation/mariadb-connector-j/commit/149ec6a626376214966c01f42d48be1b80d06056"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mariadb-corporation/mariadb-connector-j/commit/d90b9872322c76b05a48219be66bff1d33102f8a"
    },
    {
      "type": "WEB",
      "url": "https://hackerone.com/reports/3777370"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/mariadb-corporation/mariadb-connector-j"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.4.3"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.5.9"
    },
    {
      "type": "WEB",
      "url": "https://jira.mariadb.org/browse/CONJ-1325"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "MariaDB has cleartext password disclosure to a MITM on the initial-handshake"
}

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.

Action not permitted

CVE-2026-55856 (GCVE-0-2026-55856)

CLEANSTART-2026-MO09576 (CVE-2026-55856)

FKIE_CVE-2026-55856

GHSA-G9JJ-CGMH-9F38

Summary

Details

Impact

Patches

Workarounds

Tags

Sightings

Nomenclature

Related by attack behaviour