CVE-2026-111658

LOW 3.8

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

CVSS Score

3.8

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-639
Vendor	siteserver
Product	sscms
Published	Oct 16, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

High

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

Low

Availability

None

Affected Versions

SiteServer / SSCMS

0 ≤ 7.4.0

References

NVD ↗ CVE.org ↗ EPSS Data ↗

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

Credits

hieuPenguinnn