CVE-2026-45118MyBB: Contact page reflected XSS
Updated under an hour ago ()
Does this affect you?
It affects mybb. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
Do this next
Free account, 1 product
MyBB is free and open source forum software. Prior to 1.8.40, the Contact module does not validate a redirect URL or protocol correctly, resulting in an open redirect and reflected JavaScript code injection. contact.php accepts the redirect target from the from HTTP parameter in $mybb->input['from'] or the Referer HTTP header in $_SERVER['HTTP_REFERER'] and passes it to redirect() without sufficient verification. A javascript: URI becomes the target of the `Click here if you don't want to wait any longer` link because $force_redirect is true, allowing script execution when a victim selects the link. This issue is fixed in version 1.8.40.
- CVSS
- 9.3 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N
- Weakness (CWE)
- CWE-83
- 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-wf92-5q5h-qr53x-refsource-confirm
- 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.