Vulnerability-Lookup

Vulnerability from bitnami_vulndb

Published

2026-03-27 07:09

Modified

2026-03-27 07:40

Summary

Discourse vulnerable to HTML injection via prohibited iframe URLs

Details

Discourse is an open source discussion platform. Prior to versions 2026.3.0, 2026.2.1 and 2026.1.2, insufficient cleanup in the default Codepen allowed iframes value allows an attacker to trick a user into changing the URL of the main page. This issue has been fixed in versions 2026.3.0, 2026.2.1 and 2026.1.2. To workaround this issue, remove Codepen from the list of allowed iframes.

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "Bitnami",
        "name": "discourse",
        "purl": "pkg:bitnami/discourse"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2026.1.0"
            },
            {
              "fixed": "2026.1.2"
            },
            {
              "introduced": "2026.2.0"
            },
            {
              "fixed": "2026.2.1"
            },
            {
              "introduced": "2026.3.0"
            },
            {
              "fixed": "2026.3.0"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "severity": [
        {
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N",
          "type": "CVSS_V3"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-27166"
  ],
  "database_specific": {
    "cpes": [
      "cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*"
    ],
    "severity": "Medium"
  },
  "details": "Discourse is an open source discussion platform. Prior to versions 2026.3.0, 2026.2.1 and 2026.1.2, insufficient cleanup in the default Codepen allowed iframes value allows an attacker to trick a user into changing the URL of the main page. This issue has been fixed in versions 2026.3.0, 2026.2.1 and 2026.1.2. To workaround this issue, remove Codepen from the list of allowed iframes.",
  "id": "BIT-discourse-2026-27166",
  "modified": "2026-03-27T07:40:55.991Z",
  "published": "2026-03-27T07:09:46.264Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/discourse/discourse/commit/c4762a4fac2f61f52f325396b11d3aeb955ea925"
    },
    {
      "type": "WEB",
      "url": "https://github.com/discourse/discourse/security/advisories/GHSA-h653-cq78-vjj2"
    },
    {
      "type": "WEB",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-27166"
    }
  ],
  "schema_version": "1.6.2",
  "summary": "Discourse vulnerable to HTML injection via prohibited iframe URLs"
}

CVE-2026-27166 (GCVE-0-2026-27166)

Vulnerability from cvelistv5 – Published: 2026-03-19 20:29 – Updated: 2026-03-21 03:31

Title

Discourse vulnerable to HTML injection via prohibited iframe URLs

Summary

Discourse is an open source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1 and 2026.1.2, insufficient cleanup in the default Codepen allowed iframes value allows an attacker to trick a user into changing the URL of the main page. This issue has been fixed in versions 2026.3.0-latest.1, 2026.2.1 and 2026.1.2. To workaround this issue, remove Codepen from the list of allowed iframes.

Severity ?

4.1 (Medium)


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

CWE

CWE-80 - Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)

Assigner

GitHub_M

References

URL

Tags

	https://github.com/discourse/discourse/security/a…	x_refsource_CONFIRM
	https://github.com/discourse/discourse/commit/c47…	x_refsource_MISC

Impacted products

	Vendor	Product	Version
	discourse	discourse	Affected: < 2026.3.0-latest.1 Affected: >= 2026.2.0-latest, < 2026.2.1 Affected: >= 2026.1.0-latest, < 2026.1.2

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-27166",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-03-21T03:31:46.439342Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-03-21T03:31:58.296Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "discourse",
          "vendor": "discourse",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 2026.3.0-latest.1"
            },
            {
              "status": "affected",
              "version": "\u003e= 2026.2.0-latest, \u003c 2026.2.1"
            },
            {
              "status": "affected",
              "version": "\u003e= 2026.1.0-latest, \u003c 2026.1.2"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Discourse is an open source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1 and  2026.1.2, insufficient cleanup in the default Codepen allowed iframes value allows an attacker to trick a user into changing the URL of the main page. This issue has been fixed in versions 2026.3.0-latest.1, 2026.2.1 and  2026.1.2. To workaround this issue, remove Codepen from the list of allowed iframes."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 4.1,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "scope": "CHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-80",
              "description": "CWE-80: Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-03-19T20:29:22.570Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/discourse/discourse/security/advisories/GHSA-h653-cq78-vjj2",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/discourse/discourse/security/advisories/GHSA-h653-cq78-vjj2"
        },
        {
          "name": "https://github.com/discourse/discourse/commit/c4762a4fac2f61f52f325396b11d3aeb955ea925",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/discourse/discourse/commit/c4762a4fac2f61f52f325396b11d3aeb955ea925"
        }
      ],
      "source": {
        "advisory": "GHSA-h653-cq78-vjj2",
        "discovery": "UNKNOWN"
      },
      "title": "Discourse vulnerable to HTML injection via prohibited iframe URLs"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-27166",
    "datePublished": "2026-03-19T20:29:22.570Z",
    "dateReserved": "2026-02-18T00:18:53.962Z",
    "dateUpdated": "2026-03-21T03:31:58.296Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date

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.

Action not permitted

Vulnerability from bitnami_vulndb

CVE-2026-27166 (GCVE-0-2026-27166)

Tags

Sightings

Nomenclature