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Vulnerability record · CVE-2021-23835 · published 15 January 2021

CVE-2021-23835: Flatcore improper input validation vulnerability

Flatcore · Flatcore

An issue was discovered in flatCore before 2.0.0 build 139. A local file disclosure vulnerability was identified in the docs_file HTTP request body parameter for the acp interface. This can be exploited with admin access rights. The affected parameter (which retrieves the contents of the specified file) was found to be accepting malicious user input without proper sanitization, thus leading to retrieval of backend server sensitive files, e.g., /etc/passwd, SQLite database files, PHP source code, etc.

4.9 CVSS 3.1 Medium EPSS 1.7% · top 24.0% CWE-20 · Improper input validation
4.9CVSS 3.1 base score, v2 4.0
1.7%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
6References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

An issue was discovered in flatCore before 2.0.0 build 139. A local file disclosure vulnerability was identified in the docs_file HTTP request body parameter for the acp interface. This can be exploited with admin access rights. The affected parameter (which retrieves the contents of the specified file) was found to be accepting malicious user input without proper sanitization, thus leading to retrieval of backend server sensitive files, e.g., /etc/passwd, SQLite database files, PHP source code, etc.

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://packetstormsecurity.com/files/160936/flatCore-CMS-XSS-File-Disclosure-SQL-Injection.html ExploitThird Party AdvisoryVDB Entry
https://github.com/flatCore/flatCore-CMS ProductThird Party Advisory
https://sec-consult.com/vulnerability-lab/ Third Party Advisory
http://packetstormsecurity.com/files/160936/flatCore-CMS-XSS-File-Disclosure-SQL-Injection.html ExploitThird Party AdvisoryVDB Entry
https://github.com/flatCore/flatCore-CMS ProductThird Party Advisory
https://sec-consult.com/vulnerability-lab/ Third Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

8.8CVE-2019-13961Flatcore cross-site request forgery vulnerabilityA CSRF vulnerability was found in flatCore before 1.5, leading to the upload of arbitrary .php files via acp/core/files.upload-script.php.EPSS 2.3%7.2CVE-2020-17452Flatcore unrestricted file upload vulnerabilityflatCore before 1.5.7 allows upload and execution of a .php file by an admin.EPSS 2.4%7.2CVE-2019-10652Flatcore unrestricted file upload vulnerabilityAn issue was discovered in flatCore 1.4.7. acp/acp.php allows remote authenticated administrators to upload arbitrary .php files, related to the addo…EPSS 7.0%6.5CVE-2021-23837Flatcore sql injection vulnerabilityAn issue was discovered in flatCore before 2.0.0 build 139. A time-based blind SQL injection was identified in the selected_folder HTTP request body …EPSS 1.5%6.1CVE-2017-9451Flatcore cross-site scripting vulnerabilityCross site scripting (XSS) vulnerability in pages.edit_form.php in flatCore 1.4.6 allows remote attackers to inject arbitrary JavaScript via the PATH…EPSS 0.74%5.4CVE-2021-40555Flatcore cross-site scripting vulnerabilityCross site scripting (XSS) vulnerability in flatCore-CMS 2.2.15 allows attackers to execute arbitrary code via description field on the new page crea…EPSS 0.44%4.8CVE-2021-23836Flatcore cross-site scripting vulnerabilityAn issue was discovered in flatCore before 2.0.0 build 139. A stored XSS vulnerability was identified in the prefs_smtp_psw HTTP request body paramet…EPSS 0.92%4.8CVE-2021-23838Flatcore cross-site scripting vulnerabilityAn issue was discovered in flatCore before 2.0.0 build 139. A reflected XSS vulnerability was identified in the media_filter HTTP request body parame…EPSS 0.98%

Source: NIST National Vulnerability Database (record CVE-2021-23835), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.