CVE-2020-15139

XSS in MyBB

MEDIUM
6.1
CVSS Score
Published: August 10, 2020 at 09:35 PM UTC
Updated: June 17, 2026 at 02:56 AM UTC
1 product affected across 1 vendorMybb

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Severity
MEDIUM6.1
Exploit prediction
EPSS 1%

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.8.24
Affected range stops below 1.8.24, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (3)

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-79

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