Vulnerability-Lookup

Vulnerability from bitnami_vulndb

Published

2026-08-17 05:44

Modified

2026-08-17 06:10

Summary

Discourse: Onebox iframe origin allowlist enforces URL authority boundary

Details

Discourse is an open-source discussion platform. Prior to 2026.1.7, an authenticated user could submit specially formed URLs that bypassed the Onebox allowlist and embedded malicious content in a site. This issue is fixed in versions 2026.1.7, 2026.6.2, 2026.7.1, and 2026.8.0.

JSON

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Bitnami",
        "name": "discourse",
        "purl": "pkg:bitnami/discourse"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2026.1.7"
            },
            {
              "introduced": "2026.6.0"
            },
            {
              "fixed": "2026.6.2"
            },
            {
              "introduced": "2026.7.0"
            },
            {
              "fixed": "2026.7.1"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "severity": [
        {
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L",
          "type": "CVSS_V3"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-72728"
  ],
  "database_specific": {
    "cpes": [
      "cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*"
    ],
    "severity": "Medium"
  },
  "details": "Discourse is an open-source discussion platform. Prior to 2026.1.7, an authenticated user could submit specially formed URLs that bypassed the Onebox allowlist and embedded malicious content in a site. This issue is fixed in versions 2026.1.7, 2026.6.2, 2026.7.1, and 2026.8.0.",
  "id": "BIT-discourse-2026-72728",
  "modified": "2026-08-17T06:10:32.268Z",
  "published": "2026-08-17T05:44:33.304Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/discourse/discourse/commit/92eec47e8b477cb8b4ccdb237e26dc1ba8f8b76b"
    },
    {
      "type": "WEB",
      "url": "https://github.com/discourse/discourse/security/advisories/GHSA-qp9j-3v7r-wrvr"
    },
    {
      "type": "WEB",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72728"
    }
  ],
  "schema_version": "1.6.2",
  "summary": "Discourse: Onebox iframe origin allowlist enforces URL authority boundary"
}

CVE-2026-72728 (GCVE-0-2026-72728)

Vulnerability from cvelistv5 – Published: 2026-08-10 16:13 – Updated: 2026-08-10 21:10

Title

Discourse: Onebox iframe origin allowlist enforces URL authority boundary

Summary

Severity

6.3 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-10 19:01 UTC

CWE

CWE-20 - Improper Input Validation

Assigner

GitHub_M mitre root

References

2 references

URL	Tags
https://github.com/discourse/discourse/security/a…	x_refsource_CONFIRM
https://github.com/discourse/discourse/commit/92e…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
discourse	discourse	Affected: < 2026.1.7 Affected: >= 2026.6.0-latest, < 2026.6.2 Affected: >= 2026.7.0-latest, < 2026.7.1 Affected: >= 2026.8.0-latest, < 2026.8.0-latest.1

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-72728",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-10T19:01:55.334062Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-08-10T21:10:53.582Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "discourse",
          "vendor": "discourse",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 2026.1.7"
            },
            {
              "status": "affected",
              "version": "\u003e= 2026.6.0-latest, \u003c 2026.6.2"
            },
            {
              "status": "affected",
              "version": "\u003e= 2026.7.0-latest, \u003c 2026.7.1"
            },
            {
              "status": "affected",
              "version": "\u003e= 2026.8.0-latest, \u003c 2026.8.0-latest.1"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Discourse is an open-source discussion platform. Prior to 2026.1.7, an authenticated user could submit specially formed URLs that bypassed the Onebox allowlist and embedded malicious content in a site. This issue is fixed in versions 2026.1.7, 2026.6.2, 2026.7.1, and 2026.8.0-latest.1."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "LOW",
            "baseScore": 6.3,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-20",
              "description": "CWE-20: Improper Input Validation",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-10T16:13:20.965Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/discourse/discourse/security/advisories/GHSA-qp9j-3v7r-wrvr",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/discourse/discourse/security/advisories/GHSA-qp9j-3v7r-wrvr"
        },
        {
          "name": "https://github.com/discourse/discourse/commit/92eec47e8b477cb8b4ccdb237e26dc1ba8f8b76b",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/discourse/discourse/commit/92eec47e8b477cb8b4ccdb237e26dc1ba8f8b76b"
        }
      ],
      "source": {
        "advisory": "GHSA-qp9j-3v7r-wrvr",
        "discovery": "UNKNOWN"
      },
      "title": "Discourse: Onebox iframe origin allowlist enforces URL authority boundary"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-72728",
    "datePublished": "2026-08-10T16:13:20.965Z",
    "dateReserved": "2026-08-10T13:48:09.545Z",
    "dateUpdated": "2026-08-10T21:10:53.582Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.