Technical impact
This vulnerability allows an attacker to inject arbitrary JavaScript that is stored in the system and executed for every visitor to a page. The flaw originates from echoing attacker‑controlled token values in the filtertags action without applying output encoding. Because raw HTML generation is bypassed, any markup submitted through action‑attribute parameters is rendered unchanged, leading to execution of the injected script on all page renderings.
Affected Systems
The flaw affects YesWiki installations running any version earlier than 4.7.0. The product is listed as YesWiki under the Vendor "YesWiki", and the affected range is all releases below 4.7.0.
Risk and Exploitability
The CVSS score of 5.3 indicates moderate severity. No EPSS score is available, and the vulnerability is not listed in the CISA KEV catalog. An anonymous attacker can trigger the exploit simply by submitting crafted parameters to the filtertags action; no authentication or privileged access is required. The impact is a cross‑site scripting attack that can compromise all users who view the affected pages, enabling session hijacking, defacement, or credential theft.
