Vulnerability-Lookup

CVE-2026-22689 (GCVE-0-2026-22689)

Vulnerability from cvelistv5 – Published: 2026-01-10 05:46 – Updated: 2026-01-12 16:47

Title

Mailpit is vulnerable to Cross-Site WebSocket Hijacking (CSWSH) allowing unauthenticated access to emails

Summary

Mailpit is an email testing tool and API for developers. Prior to version 1.28.2, the Mailpit WebSocket server is configured to accept connections from any origin. This lack of Origin header validation introduces a Cross-Site WebSocket Hijacking (CSWSH) vulnerability. An attacker can host a malicious website that, when visited by a developer running Mailpit locally, establishes a WebSocket connection to the victim's Mailpit instance (default ws://localhost:8025). This allows the attacker to intercept sensitive data such as email contents, headers, and server statistics in real-time. This issue has been patched in version 1.28.2.

Severity

6.5 (Medium)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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 2026-01-12 16:47 UTC

CWE

CWE-1385 - Missing Origin Validation in WebSockets

Assigner

GitHub_M CNA under the mitre root

CNA scorecard C 72/100 over 7628 records in the last 180 days details

References

2 references

URL	Tags
https://github.com/axllent/mailpit/security/advis…	x_refsource_CONFIRM
https://github.com/axllent/mailpit/commit/6f1f4f3…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version	CPE status
axllent	mailpit	Affected: < 1.28.2	guessed

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-22689",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-01-12T16:47:26.726768Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-01-12T16:47:34.722Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "mailpit",
          "vendor": "axllent",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 1.28.2"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Mailpit is an email testing tool and API for developers. Prior to version 1.28.2, the Mailpit WebSocket server is configured to accept connections from any origin. This lack of Origin header validation introduces a Cross-Site WebSocket Hijacking (CSWSH) vulnerability. An attacker can host a malicious website that, when visited by a developer running Mailpit locally, establishes a WebSocket connection to the victim\u0027s Mailpit instance (default ws://localhost:8025). This allows the attacker to intercept sensitive data such as email contents, headers, and server statistics in real-time. This issue has been patched in version 1.28.2."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 6.5,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-1385",
              "description": "CWE-1385: Missing Origin Validation in WebSockets",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-01-10T05:46:13.771Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/axllent/mailpit/security/advisories/GHSA-524m-q5m7-79mm",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/axllent/mailpit/security/advisories/GHSA-524m-q5m7-79mm"
        },
        {
          "name": "https://github.com/axllent/mailpit/commit/6f1f4f34c98989fd873261018fb73830b30aec3f",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/axllent/mailpit/commit/6f1f4f34c98989fd873261018fb73830b30aec3f"
        }
      ],
      "source": {
        "advisory": "GHSA-524m-q5m7-79mm",
        "discovery": "UNKNOWN"
      },
      "title": "Mailpit is vulnerable to Cross-Site WebSocket Hijacking (CSWSH) allowing unauthenticated access to emails"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-22689",
    "datePublished": "2026-01-10T05:46:13.771Z",
    "dateReserved": "2026-01-08T19:23:09.854Z",
    "dateUpdated": "2026-01-12T16:47:34.722Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-22689",
      "date": "2026-10-19",
      "epss": "0.00239",
      "percentile": "0.14035"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "product": "mailpit",
                "vendor": "axllent",
                "versions": [
                  {
                    "status": "affected",
                    "version": "\u003c 1.28.2"
                  }
                ]
              }
            ],
            "source": "security-advisories@github.com"
          }
        ],
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:a:axllent:mailpit:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "D35BCA11-BA2A-4A42-9488-7A39F44D3AF2",
                    "versionEndExcluding": "1.28.2",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "Mailpit is an email testing tool and API for developers. Prior to version 1.28.2, the Mailpit WebSocket server is configured to accept connections from any origin. This lack of Origin header validation introduces a Cross-Site WebSocket Hijacking (CSWSH) vulnerability. An attacker can host a malicious website that, when visited by a developer running Mailpit locally, establishes a WebSocket connection to the victim\u0027s Mailpit instance (default ws://localhost:8025). This allows the attacker to intercept sensitive data such as email contents, headers, and server statistics in real-time. This issue has been patched in version 1.28.2."
          },
          {
            "lang": "es",
            "value": "Mailpit es una herramienta de prueba de correo electr\u00f3nico y API para desarrolladores. Antes de la versi\u00f3n 1.28.2, el servidor WebSocket de Mailpit est\u00e1 configurado para aceptar conexiones desde cualquier origen. Esta falta de validaci\u00f3n del encabezado Origin introduce una vulnerabilidad de Cross-Site WebSocket Hijacking (CSWSH). Un atacante puede alojar un sitio web malicioso que, cuando es visitado por un desarrollador que ejecuta Mailpit localmente, establece una conexi\u00f3n WebSocket con la instancia de Mailpit de la v\u00edctima (por defecto ws://localhost:8025). Esto permite al atacante interceptar datos sensibles como el contenido de los correos electr\u00f3nicos, los encabezados y las estad\u00edsticas del servidor en tiempo real. Este problema ha sido parcheado en la versi\u00f3n 1.28.2."
          }
        ],
        "id": "CVE-2026-22689",
        "lastModified": "2026-06-17T10:20:14.330",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "NONE",
                "baseScore": 6.5,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "NONE",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "REQUIRED",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N",
                "version": "3.1"
              },
              "exploitabilityScore": 2.8,
              "impactScore": 3.6,
              "source": "security-advisories@github.com",
              "type": "Secondary"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2026-22689",
                "options": [
                  {
                    "exploitation": "none"
                  },
                  {
                    "automatable": "no"
                  },
                  {
                    "technicalImpact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-01-12T16:47:26.726768Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2026-01-10T06:15:51.900",
        "references": [
          {
            "source": "security-advisories@github.com",
            "tags": [
              "Patch"
            ],
            "url": "https://github.com/axllent/mailpit/commit/6f1f4f34c98989fd873261018fb73830b30aec3f"
          },
          {
            "source": "security-advisories@github.com",
            "tags": [
              "Exploit",
              "Mitigation",
              "Vendor Advisory"
            ],
            "url": "https://github.com/axllent/mailpit/security/advisories/GHSA-524m-q5m7-79mm"
          }
        ],
        "sourceIdentifier": "security-advisories@github.com",
        "vulnStatus": "Analyzed",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-1385"
              }
            ],
            "source": "security-advisories@github.com",
            "type": "Secondary"
          }
        ]
      }
    },
    "redhat_vex": {
      "current_release_date": "2026-01-13T22:52:43+00:00",
      "cve": "CVE-2026-22689",
      "id": "CVE-2026-22689",
      "initial_release_date": "2026-01-01T00:00:00+00:00",
      "product_status:known_not_affected": "1",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "Mailpit is vulnerable to Cross-Site WebSocket Hijacking (CSWSH) allowing unauthenticated access to emails",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-22689.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-01-27T00:27:27Z",
      "cve": "CVE-2026-22689",
      "id": "CVE-2026-22689",
      "initial_release_date": "2026-01-27T00:27:27Z",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-22689",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-22689.json",
      "version": "2"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2026-22689",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-01-12T16:47:26.726768Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-01-12T16:47:32.112Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "product": "mailpit",
              "vendor": "axllent",
              "versions": [
                {
                  "status": "affected",
                  "version": "\u003c 1.28.2"
                }
              ]
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "value": "Mailpit is an email testing tool and API for developers. Prior to version 1.28.2, the Mailpit WebSocket server is configured to accept connections from any origin. This lack of Origin header validation introduces a Cross-Site WebSocket Hijacking (CSWSH) vulnerability. An attacker can host a malicious website that, when visited by a developer running Mailpit locally, establishes a WebSocket connection to the victim\u0027s Mailpit instance (default ws://localhost:8025). This allows the attacker to intercept sensitive data such as email contents, headers, and server statistics in real-time. This issue has been patched in version 1.28.2."
            }
          ],
          "metrics": [
            {
              "cvssV3_1": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "NONE",
                "baseScore": 6.5,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "NONE",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "REQUIRED",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N",
                "version": "3.1"
              }
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "cweId": "CWE-1385",
                  "description": "CWE-1385: Missing Origin Validation in WebSockets",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-01-10T05:46:13.771Z",
            "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
            "shortName": "GitHub_M"
          },
          "references": [
            {
              "name": "https://github.com/axllent/mailpit/security/advisories/GHSA-524m-q5m7-79mm",
              "tags": [
                "x_refsource_CONFIRM"
              ],
              "url": "https://github.com/axllent/mailpit/security/advisories/GHSA-524m-q5m7-79mm"
            },
            {
              "name": "https://github.com/axllent/mailpit/commit/6f1f4f34c98989fd873261018fb73830b30aec3f",
              "tags": [
                "x_refsource_MISC"
              ],
              "url": "https://github.com/axllent/mailpit/commit/6f1f4f34c98989fd873261018fb73830b30aec3f"
            }
          ],
          "source": {
            "advisory": "GHSA-524m-q5m7-79mm",
            "discovery": "UNKNOWN"
          },
          "title": "Mailpit is vulnerable to Cross-Site WebSocket Hijacking (CSWSH) allowing unauthenticated access to emails"
        }
      },
      "cveMetadata": {
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "assignerShortName": "GitHub_M",
        "cveId": "CVE-2026-22689",
        "datePublished": "2026-01-10T05:46:13.771Z",
        "dateReserved": "2026-01-08T19:23:09.854Z",
        "dateUpdated": "2026-01-12T16:47:34.722Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}

FKIE_CVE-2026-22689

Vulnerability from fkie_nvd - Published: 2026-01-10 06:15 - Updated: 2026-06-17 10:20

Severity

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

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/axllent/mailpit/commit/6f1f4f34c98989fd873261018fb73830b30aec3f	Patch
	security-advisories@github.com	https://github.com/axllent/mailpit/security/advisories/GHSA-524m-q5m7-79mm	Exploit, Mitigation, Vendor Advisory

Impacted products

	Vendor	Product	Version
	axllent	mailpit	*

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "mailpit",
          "vendor": "axllent",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 1.28.2"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:axllent:mailpit:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "D35BCA11-BA2A-4A42-9488-7A39F44D3AF2",
              "versionEndExcluding": "1.28.2",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Mailpit is an email testing tool and API for developers. Prior to version 1.28.2, the Mailpit WebSocket server is configured to accept connections from any origin. This lack of Origin header validation introduces a Cross-Site WebSocket Hijacking (CSWSH) vulnerability. An attacker can host a malicious website that, when visited by a developer running Mailpit locally, establishes a WebSocket connection to the victim\u0027s Mailpit instance (default ws://localhost:8025). This allows the attacker to intercept sensitive data such as email contents, headers, and server statistics in real-time. This issue has been patched in version 1.28.2."
    },
    {
      "lang": "es",
      "value": "Mailpit es una herramienta de prueba de correo electr\u00f3nico y API para desarrolladores. Antes de la versi\u00f3n 1.28.2, el servidor WebSocket de Mailpit est\u00e1 configurado para aceptar conexiones desde cualquier origen. Esta falta de validaci\u00f3n del encabezado Origin introduce una vulnerabilidad de Cross-Site WebSocket Hijacking (CSWSH). Un atacante puede alojar un sitio web malicioso que, cuando es visitado por un desarrollador que ejecuta Mailpit localmente, establece una conexi\u00f3n WebSocket con la instancia de Mailpit de la v\u00edctima (por defecto ws://localhost:8025). Esto permite al atacante interceptar datos sensibles como el contenido de los correos electr\u00f3nicos, los encabezados y las estad\u00edsticas del servidor en tiempo real. Este problema ha sido parcheado en la versi\u00f3n 1.28.2."
    }
  ],
  "id": "CVE-2026-22689",
  "lastModified": "2026-06-17T10:20:14.330",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 6.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 3.6,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-22689",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-01-12T16:47:26.726768Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-01-10T06:15:51.900",
  "references": [
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Patch"
      ],
      "url": "https://github.com/axllent/mailpit/commit/6f1f4f34c98989fd873261018fb73830b30aec3f"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Exploit",
        "Mitigation",
        "Vendor Advisory"
      ],
      "url": "https://github.com/axllent/mailpit/security/advisories/GHSA-524m-q5m7-79mm"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-1385"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}

GHSA-524M-Q5M7-79MM

Vulnerability from github – Published: 2026-01-13 15:11 – Updated: 2026-01-13 15:11

Summary

Mailpit is vulnerable to Cross-Site WebSocket Hijacking (CSWSH) allowing unauthenticated access to emails

Details

Summary The Mailpit WebSocket server is configured to accept connections from any origin. This lack of Origin header validation introduces a Cross-Site WebSocket Hijacking (CSWSH) vulnerability.

An attacker can host a malicious website that, when visited by a developer running Mailpit locally, establishes a WebSocket connection to the victim's Mailpit instance (default ws://localhost:8025). This allows the attacker to intercept sensitive data such as email contents, headers, and server statistics in real-time.

Vulnerable Code The vulnerability exists in server/websockets/client.go where the CheckOrigin function is explicitly set to return true for all requests, bypassing standard Same-Origin Policy (SOP) protections provided by the gorilla/websocket library.

https://github.com/axllent/mailpit/blob/877a9159ceeaf380d5bb0e1d84017b24d2e7b361/server/websockets/client.go#L34-L39

Impact This vulnerability impacts the Confidentiality of the data stored in or processed by Mailpit. Although Mailpit is often used as a local development tool, this vulnerability allows remote exploitation via a web browser.

Scenario: A developer has Mailpit running at localhost:8025.
Trigger: The developer visits a malicious website (or a compromised legitimate site) in the same browser.
Exploitation: The malicious site's JavaScript initiates a WebSocket connection to ws://localhost:8025/api/events. Since the origin check is disabled, the browser allows this cross-origin connection.
Data Leak: The attacker receives all broadcasted events, including full email details (subjects, sender/receiver info) and server metrics.

Attack Impact - Real-time notification of new emails - Email metadata (sender, subject, recipients) - Mailbox statistics - All WebSocket broadcast data

Recommended Fix The CheckOrigin function should be removed to allow gorilla/websocket to enforce its default safe behavior (checking that the Origin matches the Host). Alternatively, strict validation logic should be implemented.

Proposed Change (Remove unsafe check):

var upgrader = websocket.Upgrader{
    ReadBufferSize:    1024,
    WriteBufferSize:   1024,
    // CheckOrigin: func(r *http.Request) bool { return true }, // REMOVED
    EnableCompression: true,
}

Proof of Concept (PoC): To reproduce this vulnerability:

Start Mailpit (default settings).
Save the following HTML code as poc.html and serve it from a different origin (e.g., using python http.server on port 8000 or opening it directly as a file).
Open the poc_websocket_hijack.html file in your browser.
Send a test email to Mailpit or perform any action in the Mailpit UI.
Observe that the "malicious" page successfully receives the event data.

Severity

6.5 (Medium)


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

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/axllent/mailpit"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.2.6"
            },
            {
              "fixed": "1.28.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/axllent/mailpit"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.0.0-20260110031614"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-22689"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1385"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-01-13T15:11:42Z",
    "nvd_published_at": "2026-01-10T06:15:51Z",
    "severity": "MODERATE"
  },
  "details": "**Summary**\nThe Mailpit WebSocket server is configured to accept connections from any origin. This lack of Origin header validation introduces a Cross-Site WebSocket Hijacking (CSWSH) vulnerability.\n\nAn attacker can host a malicious website that, when visited by a developer running Mailpit locally, establishes a WebSocket connection to the victim\u0027s Mailpit instance (default ws://localhost:8025). This allows the attacker to intercept sensitive data such as email contents, headers, and server statistics in real-time.\n\n**Vulnerable Code**\nThe vulnerability exists in server/websockets/client.go where the CheckOrigin function is explicitly set to return true for all requests, bypassing standard Same-Origin Policy (SOP) protections provided by the gorilla/websocket library.\n\nhttps://github.com/axllent/mailpit/blob/877a9159ceeaf380d5bb0e1d84017b24d2e7b361/server/websockets/client.go#L34-L39\n\n**Impact**\nThis vulnerability impacts the Confidentiality of the data stored in or processed by Mailpit.\nAlthough Mailpit is often used as a local development tool, this vulnerability allows remote exploitation via a web browser.\n\n- **Scenario**: A developer has Mailpit running at localhost:8025.\n- **Trigger**: The developer visits a malicious website (or a compromised legitimate site) in the same browser.\n- **Exploitation**: The malicious site\u0027s JavaScript initiates a WebSocket connection to ws://localhost:8025/api/events. Since the origin check is disabled, the browser allows this cross-origin connection.\n- **Data Leak**: The attacker receives all broadcasted events, including full email details (subjects, sender/receiver info) and server metrics.\n\n**Attack Impact**\n- Real-time notification of new emails\n- Email metadata (sender, subject, recipients)\n- Mailbox statistics\n- All WebSocket broadcast data\n\n**Recommended Fix**\nThe `CheckOrigin` function should be removed to allow gorilla/websocket to enforce its default safe behavior (checking that the Origin matches the Host). Alternatively, strict validation logic should be implemented.\n\n**Proposed Change (Remove unsafe check):**\n\n```go\nvar upgrader = websocket.Upgrader{\n    ReadBufferSize:    1024,\n    WriteBufferSize:   1024,\n    // CheckOrigin: func(r *http.Request) bool { return true }, // REMOVED\n    EnableCompression: true,\n}\n```\n\n**Proof of Concept (PoC)**: To reproduce this vulnerability:\n\n- Start Mailpit (default settings).\n- Save the following HTML code as poc.html and serve it from a different origin (e.g., using python http.server on port 8000 or opening it directly as a file).\n- Open the [poc_websocket_hijack.html](https://github.com/user-attachments/files/24522726/poc_websocket_hijack.html) file in your browser.\n- Send a test email to Mailpit or perform any action in the Mailpit UI.\n- Observe that the \"malicious\" page successfully receives the event data.",
  "id": "GHSA-524m-q5m7-79mm",
  "modified": "2026-01-13T15:11:42Z",
  "published": "2026-01-13T15:11:42Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/axllent/mailpit/security/advisories/GHSA-524m-q5m7-79mm"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-22689"
    },
    {
      "type": "WEB",
      "url": "https://github.com/axllent/mailpit/commit/6f1f4f34c98989fd873261018fb73830b30aec3f"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/axllent/mailpit"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Mailpit is vulnerable to Cross-Site WebSocket Hijacking (CSWSH) allowing unauthenticated access to emails"
}

WID-SEC-W-2026-0056

Vulnerability from csaf_certbund - Published: 2026-01-11 23:00 - Updated: 2026-01-26 23:00

Summary

MailPit: Schwachstelle ermöglicht Offenlegung von Informationen

Severity

Mittel

Scope

1 vulnerability in this advisory, including CVE-2026-22689.

CVE-2026-22689

Known affected: 3 products

Open the full advisory

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.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

Order JSON

Publication & reservation Sightings KEV catalogs Other timestamps

Loading timeline…

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-2026-22689 (GCVE-0-2026-22689)

FKIE_CVE-2026-22689

GHSA-524M-Q5M7-79MM

WID-SEC-W-2026-0056

Tags

Sightings

Nomenclature

Vulnerability timeline

Related by attack behaviour