CVEvulnerability

CVE-2026-45125

5.3 MEDIUM Published 2026-08-18 Modified 2026-09-08 Official page ↗

Status: Deferred
Published: 2026-08-18
Last modified: 2026-09-08
Assigner: [email protected]
CVSS 3.1 ([email protected]): 5.3 MEDIUM — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Weaknesses: CWE-93

Description

MyBB is free and open source forum software. Prior to 1.8.40, the Email User controller does not sanitize sender names correctly, resulting in mail header injection. member.php?action=do_emailuser accepts the fromname HTTP parameter for guests or the stored username for authenticated users when the cansendemail group permission is enabled. When mail_handler is set to the default PHP mail value, the sender name is used without sanitization in Return-Path and Reply-To headers, allowing arbitrary headers to be injected with CRLF sequences. This issue is fixed in version 1.8.40.

Weakness · CWE (1)

CWE-93 Improper Neutralization of CRLF Sequences weakness

References

https://github.com/mybb/mybb/commit/5046c56b515d4593297a4f65b0c6ccb0b55baa01 github.com
https://github.com/mybb/mybb/releases/tag/mybb_1840 github.com
https://github.com/mybb/mybb/security/advisories/GHSA-f626-53q9-pqm9 github.com
https://mybb.com/versions/1.8.40 mybb.com

CVE-2026-45125

Description

Related

Weakness · CWE (1)

References