Vulnerability from bitnami_vulndb
Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, sites using wildcard patterns in the allowed_iframes setting could accept a crafted iframe URL whose allowlisted suffix appeared after a URL authority separator. The wildcard origin check matched the allowed domain text, while browser URL parsing selected a different attacker-controlled origin. A user with posting privileges could exploit the flaw through a post or a Onebox oEmbed response and cause an attacker-controlled iframe to be rendered independently of the allowlisted domain. Successful exploitation requires a site-configured wildcard iframe pattern and the ability to create a post or trigger an oEmbed request for an attacker-controlled URL. This issue is fixed in versions 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0.
{
"affected": [
{
"package": {
"ecosystem": "Bitnami",
"name": "discourse",
"purl": "pkg:bitnami/discourse"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "2026.8.0"
}
],
"type": "SEMVER"
}
],
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N",
"type": "CVSS_V3"
}
]
}
],
"aliases": [
"CVE-2026-91132"
],
"database_specific": {
"cpes": [
"cpe:2.3:a:discourse:discourse:*:*:*:*:stable:*:*:*",
"cpe:2.3:a:discourse:discourse:*:*:*:*:beta:*:*:*"
],
"severity": "Medium"
},
"details": "Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, sites using wildcard patterns in the allowed_iframes setting could accept a crafted iframe URL whose allowlisted suffix appeared after a URL authority separator. The wildcard origin check matched the allowed domain text, while browser URL parsing selected a different attacker-controlled origin. A user with posting privileges could exploit the flaw through a post or a Onebox oEmbed response and cause an attacker-controlled iframe to be rendered independently of the allowlisted domain. Successful exploitation requires a site-configured wildcard iframe pattern and the ability to create a post or trigger an oEmbed request for an attacker-controlled URL. This issue is fixed in versions 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0.",
"id": "BIT-discourse-2026-91132",
"modified": "2026-10-01T09:55:18.588Z",
"published": "2026-10-01T09:29:32.249Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/discourse/discourse/commit/80968704c1acb1d2ea2c6011dbf6c02ff13238e5"
},
{
"type": "WEB",
"url": "https://github.com/discourse/discourse/commit/d5ae0940707f95da5bc4562f7b544243e3103f8a"
},
{
"type": "WEB",
"url": "https://github.com/discourse/discourse/commit/d88e02ceb2eede4d8b851d9fe8aef753f3aa40b9"
},
{
"type": "WEB",
"url": "https://github.com/discourse/discourse/commit/db8064f2a2a2a3feb3308a1c932ac61d950c9e56"
},
{
"type": "WEB",
"url": "https://github.com/discourse/discourse/pull/42882"
},
{
"type": "WEB",
"url": "https://github.com/discourse/discourse/security/advisories/GHSA-4q3q-hph3-3rvp"
},
{
"type": "WEB",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-91132"
}
],
"schema_version": "1.6.2",
"summary": "Discourse: Wildcard iframe origin allowlist bypass via authority separators"
}
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.
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