CVE-2026-47245 MyBB: Buddy list corruption
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-47245?
CVE-2026-47245 is a medium-severity vulnerability in mybb, published on 18 Aug 2026.
Official description
MyBB is free and open source forum software. Prior to 1.8.40, the User CP Buddy/Ignore List component does not validate reciprocal buddy-list updates correctly. The usercp.php?action=do_editlists delete handler removes the selected entry from the acting user's list and then updates mybb_users.buddylist for the target account. The reciprocal update searches for the deleted target UID instead of the acting user's UID and uses the unchecked array_search() return value as an array key. A false result can be converted to index 0, removing the target account's first stored buddy while leaving the actual reciprocal entry unchanged. The uniquely identifying implementation details include false converted to index 0. This issue is fixed in version 1.8.40.
Weakness: CWE-252
Which versions are affected by CVE-2026-47245?
How do I fix CVE-2026-47245?
No fix has been published for CVE-2026-47245 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-47245 being exploited?
There is no known exploitation of CVE-2026-47245 in the wild and no public exploit code.
Sources
Also known as GHSA-w8gm-j57p-jqpc.