---
cve: "CVE-2026-91132"
severity: "MEDIUM"
cvss: 4.3
epss: "0.1%"
vendor: "discourse"
kev: false
exploited: false
published: "2026-09-24 16:57:43"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-10-05T03:13:17+02:00"
---

# CVE-2026-91132

> 4.3 MEDIUM · 🧪 PoC

## Beschreibung

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.

## CNA-Record (Kanon, cvelistV5)

- CNA: **GitHub_M**
- State: PUBLISHED
- Stand: 2026-09-29 02:57:34
- CNA-CVSS: **4.3** (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N`)

## CISA-Anreicherung (vulnrichment/ADP)

- CISA-SSVC (Coordinator, v2.0.3):
  - Exploitation: **none**
  - Automatable: **no**
  - Technical Impact: **partial**

## CVSS-Vektor

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

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Gering | warn |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Keine | good |
| I Integrität | Gering | warn |
| A Verfügbarkeit | Keine | good |

## Patch verfügbar (OSV)

- fb9247e04a826ab8e4d91168b3c4c839ec40bccc (Commit)
- 3ab62a8397926ed934b667a5db06284c45b4c774 (Commit)

## Referenzen

- <https://github.com/discourse/discourse/security/advisories/GHSA-4q3q-hph3-3rvp>
- <https://github.com/discourse/discourse/pull/42882>
- <https://github.com/discourse/discourse/commit/80968704c1acb1d2ea2c6011dbf6c02ff13238e5>
- <https://github.com/discourse/discourse/commit/d5ae0940707f95da5bc4562f7b544243e3103f8a>
- <https://github.com/discourse/discourse/commit/d88e02ceb2eede4d8b851d9fe8aef753f3aa40b9>
- <https://github.com/discourse/discourse/commit/db8064f2a2a2a3feb3308a1c932ac61d950c9e56>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-91132) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_