CVE-2025-53439
Published: 18 December 2025
Summary
CVE-2025-53439 is a high-severity PHP Remote File Inclusion (CWE-98) vulnerability in Axiomthemes Harper. Its CVSS base score is 8.1 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 32.9th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).
Deeper analysis
CVE-2025-53439 is an Improper Control of Filename for Include/Require Statement in PHP Program vulnerability, classified under CWE-98, that enables PHP Local File Inclusion in the Harper WordPress theme developed by axiomthemes. This issue affects Harper versions from n/a through 1.13 inclusive. The vulnerability stems from inadequate validation of filenames used in PHP include/require statements, allowing malicious input to reference local files.
A remote, unauthenticated attacker (PR:N) can exploit this vulnerability over the network (AV:N) without user interaction (UI:N), though it requires high attack complexity (AC:H). Successful exploitation within an unchanged scope (S:U) grants high impacts to confidentiality, integrity, and availability (C:H/I:H/A:H), potentially enabling attackers to read sensitive local files, execute arbitrary code if combined with other flaws, or disrupt theme functionality. The CVSS v3.1 base score is 8.1.
Patchstack's advisory at https://patchstack.com/database/Wordpress/Theme/harper/vulnerability/wordpress-harper-theme-1-13-local-file-inclusion-vulnerability?_s_id=cve documents the Local File Inclusion vulnerability specifically in Harper theme version 1.13, providing details relevant to mitigation for WordPress users.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-204211
Vulnerability details
Improper Control of Filename for Include/Require Statement in PHP Program ('PHP Remote File Inclusion') vulnerability in axiomthemes Harper harper allows PHP Local File Inclusion.This issue affects Harper: from n/a through <= 1.13.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
LFI in public-facing WordPress theme enables T1190 (exploit public-facing application) for initial access and T1005 (data from local system) by allowing remote reading of sensitive local files.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly addresses the inadequate validation of filenames in PHP include/require statements, preventing local file inclusion by enforcing input validation mechanisms.
Remediates the specific flaw in Harper WordPress theme versions through 1.13 by identifying, patching, and correcting the PHP local file inclusion vulnerability.
Enforces secure PHP configuration settings like open_basedir restrictions to limit accessible file paths, mitigating LFI even if filename validation is bypassed.