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TI-2020-11912 Aliases CVE-2020-15139

Cross-site scripting in MyBB

Priority MEDIUM 41CWE-79Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
Cross-site scripting
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-79.

Summary

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.

Why it matters now

EPSS 0.01317 70th percentileScored 2026-11-07
Fix Fixed MyBB (MyBB): 1.8.24

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
mybbMyBBbefore 1.8.241.8.24Patch availableCNA
  • MyBB Vendormybb Affected before 1.8.24 Fixed in 1.8.24 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:mybb:mybb:*:*:*:*:*:*:*:*before 1.8.24Vulnerablemybb
  • cpe:2.3:a:mybb:mybb:*:*:*:*:*:*:*:* Versions before 1.8.24 Vulnerable ·mybb

Remediation

  • Fix · CNA MyBB (MyBB) Fixed in 1.8.24

Timeline

  1. 2026-10-02 Threatist record created from CVE-2020-15139

References

Patch 3

  • TI-2011-04621 myBB 1.6.4 Backdoor Arbitrary Command Execution CVSS 4.0CRITICAL 10.0
  • TI-2022-08548 Remote code execution in mybb CVSS 3.1HIGH 7.2
  • TI-2023-21959 MyBB before 1.8.36 allows Code Injection by users with certain high privileges. CVSS 3.1HIGH 7.2
  • TI-2022-18641 Mail settings' command parameter injection in mybb CVSS 3.1HIGH 7.2
  • TI-2025-21092 An issue in MyBB 1.8.38 allows a remote attacker to obtain sensitive information via the… CVSS 3.1HIGH 7.6
  • TI-2025-21091 An issue in MyBB 1.8.38 allows a remote attacker to obtain sensitive information via the… CVSS 3.1HIGH 7.6
See all 139 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences