SiteServer SSCMS through 7.4.0 Cross-Site Authorization Bypass via Channels API

Advisories

SiteServer SSCMS through 7.4.0 Cross-Site Authorization Bypass via Channels API

Severity: medium
Date: 10/16/2026
Affecting: SSCMS <= 7.4.0
CVE: CVE-2026-111658
CWE: CWE-639 Authorization Bypass Through User-Controlled Key
CVSS: 5.1
CVSS V4 Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
References: https://hackmd.io/@hieuPenguinnn/sscms-cross-site-channel-idor
https://github.com/siteserver/cms/blob/sscms-v7.2.1/src/SSCMS.Web/Controllers/Admin/Cms/Channels/ChannelsController.Update.cs#L14-L31
https://github.com/siteserver/cms/blob/sscms-v7.2.1/src/SSCMS.Web/Controllers/Admin/Cms/Channels/ChannelsController.Get.cs#L16-L41
Credit: hieuPenguinnn
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.

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