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TI-2026-32951 Aliases CVE-2026-45118

MyBB: Contact page reflected XSS

Priority MEDIUM 43CWE-83Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
High · High · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00547 46th percentileScored 2026-11-07
Fix Fixed mybb (mybb): 1.8.40

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
mybbmybbbefore 1.8.401.8.40Patch availableCNA
  • mybb Vendormybb Affected before 1.8.40 Fixed in 1.8.40 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:mybb:mybb:*:*:*:*:*:*:*:*——mybb
  • cpe:2.3:a:mybb:mybb:*:*:*:*:*:*:*:* Versions — — ·mybb

Remediation

  • Fix · CNA mybb (mybb) Fixed in 1.8.40

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-45118

References

Other 3

  • TI-2011-04621 myBB 1.6.4 Backdoor Arbitrary Command Execution CVSS 4.0CRITICAL 10.0
  • TI-2022-08548 Remote code execution in mybb CVSS 3.1HIGH 7.2
  • TI-2021-22547 MyBB Timeline Plugin 1.0 Cross-Site Scripting and CSRF CVSS 4.0MEDIUM 6.9
  • TI-2023-21959 MyBB before 1.8.36 allows Code Injection by users with certain high privileges. CVSS 3.1HIGH 7.2
  • TI-2022-18641 Mail settings' command parameter injection in mybb CVSS 3.1HIGH 7.2
  • TI-2025-21092 An issue in MyBB 1.8.38 allows a remote attacker to obtain sensitive information via the… CVSS 3.1HIGH 7.6
See all 173 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences