CVE-2026-5809
Published: 11 April 2026
Summary
CVE-2026-5809 is a high-severity External Control of File Name or Path (CWE-73) vulnerability in Wordpress (inferred from references). Its CVSS base score is 7.1 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 13.9th 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 AC-3 (Access Enforcement) and SI-10 (Information Input Validation).
Deeper analysis
CVE-2026-5809 is an arbitrary file deletion vulnerability in the wpForo Forum plugin for WordPress, affecting versions up to and including 3.0.2. The issue stems from a two-step logic flaw in the topic_add() and topic_edit() action handlers, which accept arbitrary user-supplied data arrays from $_REQUEST and store them as postmeta without restricting which fields can contain array values. Because the 'body' field is included in the allowed topic fields, an attacker can supply a poisoned data[body][fileurl] with an arbitrary file path, such as wp-config.php or an absolute server path, which gets persisted to the plugin's custom postmeta database table. The vulnerability has a CVSS v3.1 base score of 7.1 (AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H) and is associated with CWE-73.
Authenticated attackers with subscriber-level access or higher can exploit this vulnerability in a two-stage process. First, they submit a topic_add or topic_edit request with the crafted data[body][fileurl] payload to store the arbitrary path in postmeta. Subsequently, they submit a topic_edit request with wpftcf_delete[]=body, triggering the add_file() method to retrieve the stored postmeta, extract the attacker-controlled fileurl, pass it through wpforo_fix_upload_dir()—which only rewrites legitimate wpforo upload paths and leaves others unchanged—and then invoke wp_delete_file() on the unvalidated path. This allows deletion of arbitrary files writable by the PHP process on the server, including critical files like wp-config.php.
The provided references point to specific locations in the vulnerable source code of wpforo version 3.0.2, including Actions.php lines 746 and 761 for the handler logic, and PostMeta.php lines 402, 421, and 523 for postmeta storage and file handling operations. No patch or mitigation details are specified in the available information.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-21676
Vulnerability details
The wpForo Forum plugin for WordPress is vulnerable to Arbitrary File Deletion in versions up to and including 3.0.2. This is due to a two-step logic flaw: the topic_add() and topic_edit() action handlers accept arbitrary user-supplied data[*] arrays from $_REQUEST…
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and store them as postmeta without restricting which fields may contain array values. Because 'body' is included in the allowed topic fields list, an attacker can supply data[body][fileurl] with an arbitrary file path (e.g., wp-config.php or an absolute server path). This poisoned fileurl is persisted to the plugin's custom postmeta database table. Subsequently, when the attacker submits wpftcf_delete[]=body on a topic_edit request, the add_file() method retrieves the stored postmeta record, extracts the attacker-controlled fileurl, passes it through wpforo_fix_upload_dir() which only rewrites legitimate wpforo upload paths and returns all other paths unchanged, and then calls wp_delete_file() on the unvalidated path. This makes it possible for authenticated attackers, with subscriber-level access and above, to delete arbitrary files writable by the PHP process on the server, including critical files such as wp-config.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Vulnerability in public-facing WordPress plugin directly enables authenticated exploitation for arbitrary file deletion on the server.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Requires validation of user-supplied inputs from $_REQUEST, preventing storage of arbitrary array structures and poisoned file paths in postmeta.
Enforces access control policies on system resources like files, ensuring only authorized paths are passed to wp_delete_file() and blocking arbitrary deletions.
Directly addresses remediation of the specific flaw in wpForo plugin versions up to 3.0.2 by identifying, patching, and testing to prevent exploitation.