CVE-2026-39387

CVE-2026-39387 is a high-severity vulnerability in Boidcms with a CVSS 3.x base score of 7.2. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-98.

Key facts

Description

BoidCMS is an open-source, PHP-based flat-file CMS for building simple websites and blogs, using JSON as its database. Versions prior to 2.1.3 are vulnerable to a critical Local File Inclusion (LFI) attack via the tpl parameter, which can lead to Remote Code Execution (RCE).The application fails to sanitize the tpl (template) parameter during page creation and updates. This parameter is passed directly to a require_once() statement without path validation. An authenticated administrator can exploit this by injecting path traversal sequences (../) into the tpl value to escape the intended theme directory and include arbitrary files — specifically, files from the server's media/ directory. When combined with the file upload functionality, this becomes a full RCE chain: an attacker can first upload a file with embedded PHP code (e.g., disguised as image data), then use the path traversal vulnerability to include that file via require_once(), executing the embedded code with web server privileges. This issue has been fixed in version 2.1.3.

Frequently asked questions

What is CVE-2026-39387?
BoidCMS is an open-source, PHP-based flat-file CMS for building simple websites and blogs, using JSON as its database. Versions prior to 2.1.3 are vulnerable to a critical Local File Inclusion (LFI) attack via the tpl parameter, which can lead to Remote Code Execution (RCE).The application fails to sanitize the tpl (template) parameter during page creation and updates. This parameter is passed directly to a require_once() statement without path validation. An authenticated administrator can exploit this by injecting path traversal sequences (../) into the tpl value to escape the intended theme directory and include arbitrary files — specifically, files from the server's media/ directory. When combined with the file upload functionality, this becomes a full RCE chain: an attacker can first upload a file with embedded PHP code (e.g., disguised as image data), then use the path traversal vulnerability to include that file via require_once(), executing the embedded code with web server privileges. This issue has been fixed in version 2.1.3.
How severe is CVE-2026-39387?
CVE-2026-39387 has a CVSS 3.x base score of 7.2, rated high severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-39387 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (50th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-39387?
CVE-2026-39387 affects Boidcms. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-39387?
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-2026-39387 have an EU (EUVD) identifier?
Yes. CVE-2026-39387 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-22804.
When was CVE-2026-39387 published?
CVE-2026-39387 was published on 2026-04-14 and last updated on 2026-06-17.

References

Affected products (1)

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