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TI-2025-31078 Aliases CVE-2025-48940

MyBB's upgrade component vulnerable to local file inclusion

Priority LOW 32CWE-22Published · Updated

Key facts

Attack vector
Network
Privileges required
High
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
High · High · High
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 version 1.8.39, the upgrade component does not validate user input properly, which allows attackers to perform local file inclusion (LFI) via a specially crafted parameter value. In order to exploit the vulnerability, the installer must be unlocked (no `install/lock` file present) and the upgrade script must be accessible (by re-installing the forum via access to `install/index.php`; when the forum has not yet been installed; or the attacker is authenticated as a forum administrator). MyBB 1.8.39 resolves this issue.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00564 47th percentileScored 2026-11-07
Fix Fixed mybb (mybb): 1.8.39

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

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 1.8.391.8.39Patch availableCNA
  • mybb Vendormybb Affected before 1.8.39 Fixed in 1.8.39 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:mybb:mybb:*:*:*:*:*:*:*:*before 1.8.39Vulnerablemybb
  • cpe:2.3:a:mybb:mybb:*:*:*:*:*:*:*:* Versions before 1.8.39 Vulnerable ·mybb

Remediation

  • Fix · CNA mybb (mybb) Fixed in 1.8.39

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-48940

References

Patch 1

Advisory 1

Other 1

  • 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-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
  • TI-2025-21091 An issue in MyBB 1.8.38 allows a remote attacker to obtain sensitive information via the… CVSS 3.1HIGH 7.6
See all 139 →

Sources

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