FKIE_CVE-2026-53961

Vulnerability from fkie_nvd - Published: 2026-07-09 22:17 - Updated: 2026-07-10 15:53
Severity
6.5 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
Summary
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.
References
security-advisories@github.comhttps://github.com/discourse/discourse/commit/3a3d315a85ef3c6aabfc7e7bb38702059784f06b
security-advisories@github.comhttps://github.com/discourse/discourse/commit/61f12e13aa1b760f81d5ff60f12e3a7e77434b94
security-advisories@github.comhttps://github.com/discourse/discourse/commit/958f0cd831d65a49ec75f05343ca2c167679f0ea
security-advisories@github.comhttps://github.com/discourse/discourse/commit/aea35190791261bab258ebab05da279e78cdd0e6
security-advisories@github.comhttps://github.com/discourse/discourse/releases/tag/v2026.1.5
security-advisories@github.comhttps://github.com/discourse/discourse/releases/tag/v2026.4.2
security-advisories@github.comhttps://github.com/discourse/discourse/releases/tag/v2026.5.1
security-advisories@github.comhttps://github.com/discourse/discourse/releases/tag/v2026.6.0
security-advisories@github.comhttps://github.com/discourse/discourse/security/advisories/GHSA-8f9m-v436-wr3x
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "discourse",
          "vendor": "discourse",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 2026.5.0-latest, \u003c 2026.5.1"
            },
            {
              "status": "affected",
              "version": "\u003e= 2026.4.0-latest, \u003c 2026.4.2"
            },
            {
              "status": "affected",
              "version": "\u003e= 2026.1.0-latest, \u003c 2026.1.5"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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": "CVE-2026-53961",
  "lastModified": "2026-07-10T15:53:08.640",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "LOW",
          "baseScore": 6.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 2.5,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-53961",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-07-10T13:44:24.781167Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-07-09T22:17:05.440",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/discourse/discourse/commit/3a3d315a85ef3c6aabfc7e7bb38702059784f06b"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/discourse/discourse/commit/61f12e13aa1b760f81d5ff60f12e3a7e77434b94"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/discourse/discourse/commit/958f0cd831d65a49ec75f05343ca2c167679f0ea"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/discourse/discourse/commit/aea35190791261bab258ebab05da279e78cdd0e6"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/discourse/discourse/releases/tag/v2026.1.5"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/discourse/discourse/releases/tag/v2026.4.2"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/discourse/discourse/releases/tag/v2026.5.1"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/discourse/discourse/releases/tag/v2026.6.0"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/discourse/discourse/security/advisories/GHSA-8f9m-v436-wr3x"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Undergoing Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-345"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}



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Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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