Vulnerability from bitnami_vulndb
Published
2026-07-15 15:56
Modified
2026-07-15 16:14
Summary
Discourse: Forged AWS SNS bounce notifications can disable a targeted user's email (missing TopicArn binding)
Details

Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, the AWS SES bounce webhook at POST /webhooks/aws verified that SNS messages were signed by Amazon but did not bind them to trusted TopicArn values, allowing any AWS account holder to publish validly signed forged Bounce notifications that revoke a targeted user email. This issue is fixed in versions 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5.

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Bitnami",
        "name": "discourse",
        "purl": "pkg:bitnami/discourse"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2026.1.0"
            },
            {
              "fixed": "2026.1.5"
            },
            {
              "introduced": "2026.4.0"
            },
            {
              "fixed": "2026.4.2"
            },
            {
              "introduced": "2026.5.0"
            },
            {
              "fixed": "2026.5.1"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "severity": [
        {
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L",
          "type": "CVSS_V3"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-53961"
  ],
  "database_specific": {
    "cpes": [
      "cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*"
    ],
    "severity": "Medium"
  },
  "details": "Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, the AWS SES bounce webhook at POST /webhooks/aws verified that SNS messages were signed by Amazon but did not bind them to trusted TopicArn values, allowing any AWS account holder to publish validly signed forged Bounce notifications that revoke a targeted user email. This issue is fixed in versions 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5.",
  "id": "BIT-discourse-2026-53961",
  "modified": "2026-07-15T16:14:00.031Z",
  "published": "2026-07-15T15:56:21.593Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/discourse/discourse/commit/3a3d315a85ef3c6aabfc7e7bb38702059784f06b"
    },
    {
      "type": "WEB",
      "url": "https://github.com/discourse/discourse/commit/61f12e13aa1b760f81d5ff60f12e3a7e77434b94"
    },
    {
      "type": "WEB",
      "url": "https://github.com/discourse/discourse/commit/958f0cd831d65a49ec75f05343ca2c167679f0ea"
    },
    {
      "type": "WEB",
      "url": "https://github.com/discourse/discourse/commit/aea35190791261bab258ebab05da279e78cdd0e6"
    },
    {
      "type": "WEB",
      "url": "https://github.com/discourse/discourse/releases/tag/v2026.1.5"
    },
    {
      "type": "WEB",
      "url": "https://github.com/discourse/discourse/releases/tag/v2026.4.2"
    },
    {
      "type": "WEB",
      "url": "https://github.com/discourse/discourse/releases/tag/v2026.5.1"
    },
    {
      "type": "WEB",
      "url": "https://github.com/discourse/discourse/releases/tag/v2026.6.0"
    },
    {
      "type": "WEB",
      "url": "https://github.com/discourse/discourse/security/advisories/GHSA-8f9m-v436-wr3x"
    },
    {
      "type": "WEB",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53961"
    }
  ],
  "schema_version": "1.6.2",
  "summary": "Discourse: Forged AWS SNS bounce notifications can disable a targeted user\u0027s email (missing TopicArn binding)"
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.