CVE-2026-18855

Link Library <= 7.9.4 - Unauthenticated Arbitrary File Deletion via link_url Parameter

2026-08-14 20:49
nudien

Strategic Overview

Status
Patched in 7.9.5
Affected Plugin
Link Library
Affected Version
<= 7.9.4
CVSS
9.1Critical
Weakness type
CWE-22 · Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CVE
CVE-2026-18855
View all Link Library vulnerabilities

At a glance

CVE-2026-18855 is a critical-severity Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') vulnerability in the Link Library WordPress plugin, affecting versions <= 7.9.4. It carries a CVSS score of 9.1 (reachable over the network; low attack complexity; high integrity, availability impact). Exploitation requires no authentication. The issue is fixed in version 7.9.5; sites on affected versions should update now. Disclosed August 2026, reported by nudien.

Vulnerability Overview

The Link Library plugin for WordPress is vulnerable to arbitrary file deletion due to insufficient file path validation in the ll_delete_link_fields function in all versions up to, and including, 7.9.4 This makes it possible for unauthenticated attackers to delete arbitrary files on the server, which can easily lead to remote code execution when the right file is deleted (such as wp-config.php). Exploitation requires the administrator to have enabled the 'Delete local file on link deletion' plugin option (disabled by default) and to subsequently permanently delete the attacker-submitted link, which is a routine moderation action.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user. A successful exploit has high impact on integrity, availability.

CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Reaching this weakness in Link Library <= 7.9.4 takes no account at all. Path traversal happens when user-controlled text is used to build a filesystem path without being constrained to an intended directory, so sequences like ../ walk the resolved path somewhere else.

Depending on the operation, it means reading files outside the intended folder — wp-config.php being the usual target — or writing to and deleting paths the web server can touch. For Link Library the fix is 7.9.5: builds <= 7.9.4 are affected, anything from 7.9.5 onward is not.

Remediation

Update to version 7.9.5, or a newer patched version

How does WordSec protect against this?

Requests carrying this pattern arrive without a session, so nothing upstream of the firewall gets a chance to reject them: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Link Library 7.9.5 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Login Security
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2026-18855https://www.wordfence.com/threat-intel/vulnerabilities/id/41327dfa-db64-476a-a263-7bd4f69fb857https://nvd.nist.gov/vuln/detail/CVE-2026-18855

Related records

Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C