CVE-2026-47245

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.

• CWE-252

• https://github.com/mybb/mybb/commit/0557718f27503034fb1c2768729a2fb8239bba65
• https://github.com/mybb/mybb/releases/tag/mybb_1840
• https://github.com/mybb/mybb/security/advisories/GHSA-w8gm-j57p-jqpc
• https://mybb.com/versions/1.8.40

Published

Aug 18, 2026

Last Modified

Sep 8, 2026

Status

Deferred

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
• AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.

• CVE-2026-4724Undefined behavior in the Audio/Video component. This vulner…9.1
• CVE-2026-47240Net::IMAP implements Internet Message Access Protocol (IMAP)…5.8
• CVE-2026-47241Net::IMAP implements Internet Message Access Protocol (IMAP)…2.1
• CVE-2026-47242Net::IMAP implements Internet Message Access Protocol (IMAP)…5.8
• CVE-2026-47243Kata Containers is an open source project focusing on a stan…9.2
• CVE-2026-47244Netty is a network application framework for development of …5.3
• CVE-2026-47247libheif is a HEIF and AVIF file format decoder and encoder. …7.5
• CVE-2026-47248Parse Server is an open source backend that can be deployed …6.9
• CVE-2026-47249Klever-Go is the Go implementation of the Klever blockchain …7.5
• CVE-2026-4725Sandbox escape due to use-after-free in the Graphics: Canvas…10
• CVE-2026-47250mcp-server-kubernetes is a Model Context Protocol server for…6.1
• CVE-2026-47251libheif is a HEIF and AVIF file format decoder and encoder. …6.1