CVE-2026-111658

Description

SiteServer SSCMS through 7.4.0 contains an authorization bypass vulnerability in ChannelsController that allows site-scoped administrators to access other sites' channels by supplying foreign channel IDs. Attackers with Channels permission on one site can read and overwrite another site's channel names, file paths, templates, link URLs, and custom fields, breaking multi-site isolation.

References

• https://github.com/siteserver/cms/blob/sscms-v7.2.1/src/SSCMS.Web/Controllers/Admin/Cms/Channels/ChannelsController.Get.cs#L16-L41
• https://github.com/siteserver/cms/blob/sscms-v7.2.1/src/SSCMS.Web/Controllers/Admin/Cms/Channels/ChannelsController.Update.cs#L14-L31
• https://hackmd.io/@hieuPenguinnn/sscms-cross-site-channel-idor
• https://www.vulncheck.com/advisories/siteserver-sscms-through-7.4.0-cross-site-authorization-bypass-via-channels-api