VulnerabilityDeferred

CVE-2026-45119

Prior to 1.8.40, the Admin CP UTF-8 Conversion module does not validate certain requests correctly, allowing same-site attackers to alter table encoding and deny service with a specially crafted URL.

MEDIUM 4.6EPSS 0.13%

Does this matter?

Lower severity and a low EPSS score (0.13%). Track it; it rarely justifies an emergency change on its own.

Description

MyBB is free and open source forum software. Prior to 1.8.40, the Admin CP UTF-8 Conversion module does not validate certain requests correctly, allowing same-site attackers to alter table encoding and deny service with a specially crafted URL. The do=all control flow in admin/modules/tools/system_health.php performs ALTER TABLE operations, column rewrite phases, and fulltext index rebuilds on GET requests for the database table named by the table parameter without request verification. The uniquely identifying implementation details include GET requests without request verification. This issue is fixed in version 1.8.40.

CVSS 3.1: 4.6 MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:L
EPSS: 0.13% probability · 3th percentile
CISA KEV: Not listed
Weakness: CWE-352
Source: security-advisories@github.com

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.