A stored server‑side template injection exists in the Bazar semantic template feature of YesWiki. An authenticated administrator can insert arbitrary Twig expressions into the bn_sem_template field, which is later evaluated when a public semantic endpoint is accessed. This injection flaw can be exploited to execute arbitrary server‑side code, compromising the integrity and confidentiality of the system.

YesWiki yeswiki is affected in all releases prior to 4.6.6, with the vulnerability fixed in version 4.6.6. Administrators of these installations are the primary users who can trigger the exploitation path.

The vulnerability has a CVSS score of 7.1, indicating a high severity impact when exploited. No EPSS data is currently available and the issue is not listed in the CISA KEV catalog, but the nature of the flaw provides a clear attack vector via privileged admin access and public semantic endpoints, making successful exploitation reasonably likely for an attacker with the required credentials.