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CVE-2026-45119

MyBB: ACP UTF-8 Conversion CSRF

Published: Aug 18, 2026Updated: Aug 19, 2026 Sources: CVE List NVDCWE-352
4.6MEDIUM
NVD MITRE
EPSS Score
0.1%
Top 97.1%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available
Self-Check
Not available

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:LUI:RS:UC:NI:LA:L
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:LPrivileges Required
Low
UI:RUser Interaction
Required
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:LIntegrity
Low
A:LAvailability
Low
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Weaknesses

CWE-352

Affected Products

mybb
oss-projectaka mybb forums
mybb
Web & CMS Plugins

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

1 technique
Initial Access
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References

https://github.com/mybb/mybb/security/advisories/GHSA-p48q-4vgf-q7x8
github.com
https://github.com/mybb/mybb/commit/70d445d14c8350cc014be66f7874611abef70ab4
github.com
https://github.com/mybb/mybb/releases/tag/mybb_1840
github.com
and 1 more references View all →

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