Detect WordPress Core Interpretation Conflict Vulnerability (CVE-2026-63030) in Splunk

WordPress Core contains an interpretation conflict vulnerability (CWE-436) fixed in WordPress 7.0.2, in which differing parsing/interpretation behavior between components of the request-handling pipeline (e.g., PHP, web server, and WordPress core routing/sanitization layers) allows an attacker to smuggle or disguise malicious input so it is treated differently downstream than upstream validation expected. This class of flaw is commonly abused to bypass input filtering, achieve request smuggling-style effects against reverse proxies/CDNs fronting WordPress, or slip malicious payloads (e.g., leading to file write, privilege escalation, or authentication bypass) past security controls that assume a single canonical interpretation of the request. The vulnerability is listed in CISA KEV, indicating confirmed active exploitation in the wild, and is subject to CISA BOD 26-04 remediation timelines for federal and high-risk entities. No CVSS score has been published at time of writing; PoC details are not publicly available, but active exploitation implies working exploit code exists among threat actors. Detection focuses on anomalous WordPress core request patterns consistent with interpretation-conflict abuse: malformed/duplicate headers, ambiguous content-length/transfer-encoding combinations, unusual URL encoding or path traversal-like sequences hitting wp-admin/wp-login/wp-json endpoints, and post-exploitation indicators such as new admin users, unexpected plugin/theme file writes, or webshell drops shortly after anomalous requests.