W3 Total Cache - Path Traversal (CVE-2026-18051)

CVE-2026-18051 is a critical path traversal vulnerability in the W3 Total Cache WordPress plugin before version 2.10.5. Unauthenticated attackers can exploit improper request-path validation to write or overwrite files in existing server directories, including files outside the web root. On Apache servers, this can overwrite .htaccess files, disrupting site availability and removing security rules that other protections rely on.

CrowdSec has been tracking this vulnerability and its exploits since 27th of October 2026.

Data from the CrowdSec community indicates that exploitation of CVE-2026-18051 is highly selective and intelligence-driven. Threat actors use advanced reconnaissance and carefully choose their targets, often as part of sophisticated campaigns or advanced persistent threat operations. Data from the CrowdSec community also indicates a gradual decrease in attacks targeting CVE-2026-18051. While still present in the wild, exploitation levels have dropped noticeably week-over-week. This may signal that the vulnerability is becoming less relevant or that defenses are improving fast enough for attackers to lose interest.

Attackers target WordPress search URLs under /search/, using encoded ..\\ traversal sequences to manipulate cache file paths and write files. Successful exploitation may overwrite files such as .htaccess.