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CVE

CVE-2026-45117

MyBB: Installer database configuration RCE
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CVE

CVE-2026-45117

MyBB: Installer database configuration RCE

MyBB is free and open source forum software. From 1.8.13 until 1.8.40, the installer module does not properly escape user-supplied database configuration values written to the configuration file, resulting in PHP code injection and remote code execution when the installer is available. install/index.php processes the values with addcslashes(), but the $characters argument added in MyBB 1.8.13 does not include the backslash character, allowing crafted input to escape the generated PHP string. The uniquely identifying implementation details include introduced in MyBB 1.8.13. This issue is fixed in version 1.8.40.

Package Versions Affected

Package Version
patch Availability
No items found.

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CVSS Version

Severity
Base Score
CVSS Version
Score Vector
C
H
U
9.8
-
3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
C
H
U
0
-
3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
C
H
U
-

Related Resources

No items found.

References

https://github.com/mybb/mybb/releases/tag/mybb_1840, https://mybb.com/versions/1.8.40, https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45117.json, https://github.com/mybb/mybb/security/advisories/GHSA-gpc4-77rp-3xqr, https://nvd.nist.gov/vuln/detail/CVE-2026-45117, https://github.com/mybb/mybb/commit/0fe713e3b964bfc878ea65bdd9f746f585f6ebbf

Severity

9.8

CVSS Score
0
10

Basic Information

Base CVSS
9.8
EPSS Probability
0.01149%
EPSS Percentile
0.65576%
Introduced Version
0
Fix Available
e9942c6d19ac1709b3df7357cfb8810774c8d3ac

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