MyBB 1.8.9 Released – Security & Maintenance Release

MyBB 1.8.9 is now available from the MyBB website, and is a security and maintenance release.

What’s added/changed in this version?

This release fixes 1 security vulnerability and 52 reported issues causing incorrect functionality of MyBB. Please be aware that not all issues have been fixed in this version in order to provide easy to manage updates.

  • Vulnerabilities:
    • Low risk: CSRF issue when removing subscriptions – reported by Devilshakerz

Please view the 1.8.9 changes on the Docs site for more information about the changes in this version.

Please note, that you do need to run the upgrade script for this version.

Upgrading from 1.8.8 and Other Versions

Before performing any upgrade please remember to backup your forum’s files and database and store them safely. If you have edited core files, including language files, please make sure you make a changelog for these changes so you can make them again (if necessary) once the upgrade is complete.

To upgrade, follow the Upgrading process. The upgrade script is required. There are changes to 18 language files and 85 templates were changed or added.

If you’re using MyBB 1.8.8:

  • Download and use the Changed Files Package
    • MD5: cd4f736ef9c3b20136203350468ad23d
    • SHA1: 3208c50d35aacc9d51d195de8ccc33aed1e3b1c6
    • SHA256: c153236148457ae1ea2a62b8c7c15a11a093ab436ae6ea416c8cf9ca2bf53687
    • SHA512: 1e16aeae125a1e2edf966866d53c51ce9b5d7568214c6244efc4976d4af16186e3f9f10f8eafbd5f5de3210a1fada6635fea7c97bb09afe3d1c9bf3e368bfa3d
  • Follow the Docs Upgrading Instructions

If you’re using MyBB 1.8.7 or lower:

  • Download and use the full 1.8.9 Release Package
    • MD5: b1a8fbdb4d8a888f7757be14cd658662
    • SHA1: d30f95de2e2142a46e4a34e0d26a8d3f5762cb22
    • SHA256: cc4a015edb96b587a74b3d54c00bf2ecd4be6ff2efec8b24caae90c538b42e89
    • SHA512: b18ffd2797f2f6fc775fda7b47c6d4b63d36f0e8c57ee1ce6797de8e600f741df2cc1bce713723b12d2374e723289641ab3a10248f5ba53672f5765bed836056
  • Follow the Docs Upgrading Instructions

To update existing themes the following CSS code needs to be added to global.css:

.deleted_post_hidden {
	border-top: 2px solid #ccc;
	padding: 15px;

.deleted_post_collapsed {
	border-top: 3px solid #333;
	padding: 15px;

.deleted_post_collapsed .show_deleted_post {
	margin-top: -15px;

.deleted_post_collapsed .show_deleted_post a.button span {
	background-position: 0 -400px;

Note: JavaScript-related bugs discovered
We have found that some JavaScript-based functions (like the inline moderation) may not work properly under MyBB 1.8.9. Please refer to the Community thread for detailed instructions on how to patch the code while we prepare a fixed package.

Reporting MyBB security vulnerabilities

If you think you’ve found a vulnerability in MyBB, we advise you not to publicly post it on these forums or publicly release information about it elsewhere until we’ve had time to prepare and release a patch.

As always, you can send through security related messages on the MyBB website from the Contact Us page or in our Private Inquiries forum – where you can start a new thread that only you and the MyBB Team can see.


MyBB Team

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