CVE-2025-15057
Published: 09 January 2026
Summary
CVE-2025-15057 is a high-severity Cross-site Scripting (CWE-79) vulnerability in Wordpress (inferred from references). Its CVSS base score is 7.2 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 10.6th 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-15 (Information Output Filtering).
Deeper analysis
CVE-2025-15057 is a stored cross-site scripting (XSS) vulnerability in the SlimStat Analytics plugin for WordPress, affecting all versions up to and including 5.3.3. The flaw arises from insufficient input sanitization and output escaping of the `fh` (fingerprint) parameter, which allows malicious payloads to be stored directly in the database. It has been assigned a CVSS v3.1 base score of 7.2 (AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N) and maps to CWE-79 (Cross-Site Scripting). Published on January 9, 2026, the vulnerability enables injection of arbitrary web scripts into pages.
Unauthenticated attackers can exploit this vulnerability remotely with low complexity and no user interaction required. By submitting a crafted `fh` parameter, attackers store malicious JavaScript in the database, which executes in the context of an administrator's browser whenever they access the Real-time Access Log report. This can lead to low-level confidentiality and integrity impacts, such as session hijacking, data theft, or further site compromise, due to the changed scope (S:C).
Mitigation details are available in the referenced advisories: the WordPress plugin trac changeset 3428488 indicates a patch has been applied, and the Wordfence threat intelligence page provides additional vulnerability details and scanning recommendations for affected sites. Security practitioners should update to a version beyond 5.3.3 and review access logs for suspicious `fh` values.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-1792
Vulnerability details
The SlimStat Analytics plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the `fh` (fingerprint) parameter in all versions up to, and including, 5.3.3. This is due to insufficient input sanitization and output escaping on the fingerprint value stored…
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in the database. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever an administrator views the Real-time Access Log report.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Stored XSS in public-facing WordPress plugin directly enables remote script injection (T1190) and JavaScript execution in admin context (T1059.007).
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly requires validation and sanitization of untrusted input such as the fh fingerprint parameter before it is stored in the database.
Requires filtering or escaping of information on output so that stored malicious scripts are not executed in administrator browsers.
Deploys malicious-code detection mechanisms at entry/exit points that can identify and block XSS payloads submitted via the fh parameter.