High severity · published Apr 28, 2026
CVE-2026-27760
OpenCATS PHP Code Injection via installer AJAX endpoint
8.1
CVSS
33%
EPSS
No
On KEV
Description
OpenCATS prior to commit 3002a29 contains a PHP code injection vulnerability in the installer AJAX endpoint that allows unauthenticated attackers to execute arbitrary code by injecting PHP statements into the databaseConnectivity action parameter. Attackers can break out of the define() string context in config.php using a single quote and statement separator to inject malicious PHP code that persists and executes on every subsequent page load when the installation wizard remains incomplete.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)33.0% · higher than 98% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
OP
OpenCATS · opencats
through 0.9.7.4 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-27760
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-27760
chocapikk.com
https://chocapikk.com/posts/2026/opencats-installer-rce/
github.com
https://github.com/opencats/OpenCATS/blob/46e4727/lib/CATSUtility.php#L142-L172
github.com
https://github.com/opencats/OpenCATS/blob/46e4727/modules/install/ajax/ui.php#L130
github.com
https://github.com/opencats/OpenCATS/commit/3002a29f4c3cada1aa2c4f3d4ae4e189906606b6
github.com
https://github.com/opencats/OpenCATS/pull/706
www.vulncheck.com
https://www.vulncheck.com/advisories/opencats-php-code-injection-via-installer-ajax-endpoint
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