---
cve: "CVE-2020-15139"
severity: "HIGH"
cvss: 8.8
epss: "1.3%"
vendor: "MyBB"
kev: false
exploited: false
published: "2020-08-10 22:15:14"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-07T07:40:09+02:00"
---

# CVE-2020-15139

> 8.8 HIGH · 🧪 PoC

## Beschreibung

In MyBB before version 1.8.24, the custom MyCode (BBCode) for the visual editor doesn't escape input properly when rendering HTML, resulting in a DOM-based XSS vulnerability. The weakness can be exploited by pointing a victim to a page where the visual editor is active (e.g. as a post or Private Message) and operates on a maliciously crafted MyCode message. This may occur on pages where message content is pre-filled using a GET/POST parameter, or on reply pages where a previously saved malicious message is quoted. After upgrading MyBB to 1.8.24, make sure to update the version attribute in the `codebuttons` template for non-default themes to serve the latest version of the patched `jscripts/bbcodes_sceditor.js` file.

## CVSS-Vektor

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

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

## Patch verfügbar (OSV)

- 37ad29dcd25489a37bdd89ebac761f22492558b0 (Commit)

## Referenzen

- <https://github.com/mybb/mybb/security/advisories/GHSA-37h7-vfv6-f8rj>
- <https://github.com/mybb/mybb/commit/37ad29dcd25489a37bdd89ebac761f22492558b0>
- <https://mybb.com/versions/1.8.24/>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2020-15139) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_