CVE-2017-18264

Severity: critical (CVSS 9.8 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.8% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2018-05-01 · updated 2026-06-17

Description

An issue was discovered in libraries/common.inc.php in phpMyAdmin 4.0 before 4.0.10.20, 4.4.x, 4.6.x, and 4.7.0 prereleases. The restrictions caused by $cfg['Servers'][$i]['AllowNoPassword'] = false are bypassed under certain PHP versions (e.g., version 5). This can allow the login of users who have no password set even if the administrator has set $cfg['Servers'][$i]['AllowNoPassword'] to false (which is also the default). This occurs because some implementations of the PHP substr function return false when given '' as the first argument.

Affected products

Debian Linux: 8.0
phpMyAdmin: from 4.0.0 before 4.0.10.20; from 4.4.0 through 4.4.15.10; from 4.6.0 through 4.6.6; 4.7.0-beta1, 4.7.0-rc1 — fixed in 4.0.10.20

How to fix

Upgrade to a fixed version: phpMyAdmin 4.0.10.20. Check the vendor advisory for mitigations.

References

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