CVE-2025-2746

What it actually does

CVE-2025-2746 is an authentication bypass in Kentico Xperience's Staging Sync Server digest-authentication handling. Affected versions through Xperience 13.0.172 can incorrectly process staging authentication when the digest username is empty and SHA1 password handling is involved, allowing an unauthenticated remote attacker to be treated as authorized for staging synchronization operations. Because staging synchronization can create, modify, or delete administrative objects, successful exploitation can lead to administrative control of CMS configuration and content-related objects without valid credentials.

Why it matters to the business

A successful attack can let an external attacker take control of important Kentico Xperience administrative objects, potentially changing website content, adding malicious functionality, disrupting publishing workflows, or establishing persistence inside the CMS. The flaw is high urgency because it has a CVSS score of 9.8, high EPSS likelihood, is listed in CISA KEV with a remediation due date of 2025-11-10, and has been observed as actively exploited in the wild. Organizations running exposed Kentico Xperience staging endpoints are at elevated risk of compromise, operational disruption, reputational harm, and follow-on attacks through the public website or CMS administration layer.

How an attack unfolds

An attacker first identifies a Kentico Xperience instance and probes for the Staging Sync Server endpoint, commonly exposed for content or object synchronization between environments. The attacker then sends crafted digest-authenticated requests that use the vulnerable empty-username handling path. If the target is running Xperience through 13.0.172 and the staging service is reachable, the application may accept the request without a valid staging user credential. The attacker can then invoke staging synchronization functionality to manipulate administrative objects, such as configuration, content, page objects, or other CMS-managed items. In a real intrusion, the attacker may use this access to change site behavior, add malicious content or scripts, create persistence through CMS objects, or pivot toward administrator access and broader application compromise. Public reporting and KEV inclusion indicate exploitation is active in the wild, so investigation should assume exposed unpatched systems may have been targeted.

How to fix it

Upgrade Kentico Xperience to a vendor-fixed release newer than 13.0.172, or apply the official Kentico hotfix/security update that remediates this vulnerability. If an immediate upgrade is not possible, restrict access to the Staging Sync Server endpoint to trusted internal IP addresses or VPN-only networks, disable staging synchronization if it is not required, and block unauthenticated internet access to staging web service paths at the web server, reverse proxy, WAF, or network firewall. Rotate staging synchronization credentials after patching because exploitation may have exposed or bypassed trust assumptions around the staging channel. Review CMS administrative objects and staging tasks for unauthorized changes before returning the service to normal operation.

How to confirm the fix worked

Confirm the installed Kentico Xperience version is later than 13.0.172 or that the vendor hotfix containing the authentication-bypass fix is installed. Verify the Staging Sync Server endpoint is not publicly reachable unless explicitly required and protected by network allowlisting. Test that requests to the staging synchronization endpoint using digest authentication with an empty username, missing username, or malformed digest fields are rejected with 401/403 responses and do not perform synchronization actions. Review application, IIS, reverse-proxy, and WAF logs to confirm no successful staging sync operations occurred from untrusted IP addresses before and after remediation. Validate that no unauthorized CMS objects, users, pages, templates, scheduled tasks, transformations, or scripts were created or modified during the exposure window.

Typical attack path

1. Fingerprint the target as Kentico Xperience and identify the deployed version or CMS-specific paths.
2. Probe for the Staging Sync Server endpoint, especially staging synchronization web service paths.
3. Send crafted HTTP requests using digest authentication with an empty username or malformed digest-authentication fields that exercise the vulnerable password-handling path.
4. Gain unauthorized access to staging synchronization operations without valid credentials.
5. Use staging sync capabilities to create, modify, or delete administrative objects in the CMS.
6. Modify website content, CMS configuration, templates, scripts, users, or other managed objects to achieve persistence, defacement, data access, or further application compromise.
7. Clean up obvious request artifacts or continue using the staging endpoint for repeat access.

How to detect it

Investigate IIS, web server, reverse proxy, WAF, EDR, and Kentico application logs for requests to the staging synchronization endpoint, especially from internet sources, unusual geographies, hosting providers, or IPs that do not belong to approved staging partners. Search for HTTP Authorization headers using Digest authentication where the username value is empty, missing, malformed, or otherwise abnormal. Review logs around POST requests to Kentico staging web service paths and correlate them with CMS object modifications, staging task execution, administrative object changes, newly created users, role changes, template changes, page modifications, scheduled task changes, uploaded files, or injected scripts. Because this vulnerability is actively exploited in the wild, treat any successful staging request from an untrusted source as suspicious even if the request appears to have authenticated. Preserve web access logs, Kentico event logs, staging task history, CMS audit logs, and database/application backups for the suspected compromise window. Look for post-exploitation behavior such as unexpected content edits, new privileged accounts, modified page templates, added JavaScript, new scheduled tasks, unknown files in web-accessible directories, or repeated staging calls from the same external IP.

• /CMSPages/Staging/SyncServer.asmx
• POST /CMSPages/Staging/SyncServer.asmx
• Authorization: Digest username=""
• Authorization: Digest username=",
• Authorization: Digest, username=""
• Digest username=""
• SyncServer.asmx
• /CMSPages/Staging/
• SOAPAction:

What your security team should do

• Immediately inventory Kentico Xperience instances and identify any running version 13.0.172 or earlier.
• Prioritize emergency patching of any internet-facing Kentico Xperience instance because the vulnerability is in CISA KEV and exploitation is active in the wild.
• Restrict or disable Staging Sync Server access until patching is complete, using IP allowlists, VPN requirements, reverse-proxy rules, or WAF controls.
• Hunt historical logs for access to staging synchronization endpoints, especially digest-authentication requests with empty usernames or anomalous Authorization headers.
• Review Kentico administrative objects, CMS users, roles, scheduled tasks, templates, web parts, transformations, and content changes for unauthorized modifications.
• Rotate staging synchronization credentials and relevant CMS administrative credentials after remediation.
• Add monitoring rules for access to Kentico staging web service paths and alert on any requests from non-administrative networks.
• Meet or beat the CISA KEV remediation due date of 2025-11-10 for all applicable systems.