CVE-2026-47245MyBB: Buddy list corruption
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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Free account, 1 product
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.
- CVSS
- 4.3 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
- Weakness (CWE)
- CWE-252
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Deferred
- Record last updated
- Aug 18, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
mybb mybb mybb:mybb (from the name) | before 1.8.40 | CNA record |
References
- https://github.com/mybb/mybb/security/advisories/GHSA-w8gm-j57p-jqpcx-refsource-confirm
- https://github.com/mybb/mybb/commit/0557718f27503034fb1c2768729a2fb8239bba65x-refsource-misc
- https://github.com/mybb/mybb/releases/tag/mybb_1840x-refsource-misc
- https://mybb.com/versions/1.8.40x-refsource-misc
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.