CVE-2026-27760
CVE-2026-27760 is a high-severity vulnerability with a CVSS 3.x base score of 8.1. Its EPSS exploit-prediction score of 22% places it in the 97th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-94.
Key facts
- Severity: High (CVSS 3.x base score 8.1)
- CVSS v4: 9.2
- EPSS exploit prediction: 22% (97th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-26052
- Weakness: CWE-94
- Published:
- Last modified:
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.
Frequently asked questions
- What is CVE-2026-27760?
- 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.
- How severe is CVE-2026-27760?
- CVE-2026-27760 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2026-27760 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 22% (97th percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-27760?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2026-27760 have an EU (EUVD) identifier?
- Yes. CVE-2026-27760 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-26052.
- When was CVE-2026-27760 published?
- CVE-2026-27760 was published on 2026-04-28 and last updated on 2026-06-17.
References
- https://chocapikk.com/posts/2026/opencats-installer-rce/
- https://github.com/opencats/OpenCATS/blob/46e4727/lib/CATSUtility.php#L142-L172
- https://github.com/opencats/OpenCATS/blob/46e4727/modules/install/ajax/ui.php#L130
- https://github.com/opencats/OpenCATS/commit/3002a29f4c3cada1aa2c4f3d4ae4e189906606b6
- https://github.com/opencats/OpenCATS/pull/706
- https://www.vulncheck.com/advisories/opencats-php-code-injection-via-installer-ajax-endpoint
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