CVE-2025-2749
Kentico Xperience Path Traversal Vulnerability
Description
CVE-2025-2749 is a path traversal vulnerability (CWE-22) in Kentico Xperience, a .NET-based enterprise content management system (CMS) widely used for digital experience platforms and corporate websites. The flaw exists in Kentico's Staging Sync Server component, which handles content synchronization between Xperience environments (e.g., from a staging environment to production). An authenticated user with access to the Staging Sync Server can craft a synchronization request that writes arbitrary data to locations outside the intended upload directory by supplying a path-traversal sequence (e.g., "../") in file path parameters, enabling an arbitrary file write condition on the server's local filesystem. While authentication is required — reducing the immediate attacker population — arbitrary file write on a web server filesystem is a high-impact primitive that commonly leads to remote code execution by overwriting executable files, application configuration, or placing web shells in web-accessible directories. CISA added CVE-2025-2749 to the Known Exploited Vulnerabilities (KEV) catalog on April 20, 2026, with a remediation due date of May 4, 2026. The EPSS score is 0.03024, placing this vulnerability at the 86.7th percentile — in the top 15% of all CVEs by predicted exploitation probability, a notably high ranking that reflects active attacker interest despite the authentication requirement.
KEV Information
CVSS Score
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:HOpen in CalculatorCWEs
Affected Products
| Vendor | Product | Version |
|---|---|---|
| kentico | xperience | <= 13.0.178 |
References
- https://devnet.kentico.com/download/hotfixes(Patch)
- https://labs.watchtowr.com/bypassing-authentication-like-its-the-90s-pre-auth-rce-chain-s-in-kentico-xperience-cms/(Exploit, Third Party Advisory)
- https://www.vulncheck.com/advisories/kentico-xperience-staging-media-file-upload-authenticated-rce(Third Party Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-2749(US Government Resource)
Weakness Type
CWE-22: Improper Limitation of a Pathname to a Restricted Directory (Path Traversal)
CWE-22, commonly known as path traversal or directory traversal, occurs when software uses external input to construct a filesystem path that should be restricted to a controlled directory, but fails to properly neutralize special path elements such as "../" (dot-dot-slash). An attacker who can supply filename or path parameters to a file-handling function can escape the intended directory boundary and read from or write to arbitrary filesystem locations. Write-capable path traversal is generally considered higher severity than read-only traversal because it enables content injection, configuration manipulation, and in many server environments, remote code execution via web shells or overwriting of application binaries and scripts.
In CVE-2025-2749, the path traversal exists within Kentico Xperience's Staging Sync Server, which is designed to accept file payloads from a staging environment and write them to designated synchronization directories on the target server. The Staging Sync Server fails to canonicalize or validate the caller-supplied file path before performing the write operation, allowing a traversal sequence to redirect the written file to any path reachable by the application process's operating system account. On a .NET IIS-hosted CMS, the application pool identity often has broad write access to the web root and application directories, making this a particularly high-impact write primitive. Learn more: CWE-22 — Improper Limitation of a Pathname to a Restricted Directory
Impact Analysis
CVE-2025-2749 has been assessed as MEDIUM-HIGH severity. No formal NVD CVSS score was available at the time of writing; the following analysis is contextually derived from the vulnerability's characteristics.
Attack Vector (Network): The Kentico Xperience Staging Sync Server is a network-accessible service endpoint, typically exposed within internal networks or staging/production infrastructure. Exploitation occurs over HTTP/HTTPS.
Attack Complexity (Low): Path traversal attacks are conceptually simple and well-understood. Once an attacker possesses valid credentials and can send HTTP requests to the Staging Sync Server endpoint, exploitation requires only constructing a request with a traversal-encoded path parameter. No race conditions, heap grooming, or complex prerequisite state are needed.
Privileges Required (Low): Authentication is required, which represents the primary barrier to exploitation. However, any authenticated Kentico Xperience user with staging permissions can exploit the vulnerability. In enterprise CMS deployments, staging access is often granted broadly to content editors, developers, and agency partners — significantly expanding the potential attacker population beyond system administrators.
User Interaction (None): Exploitation is fully attacker-driven after authentication.
Impact Analysis — Confidentiality (Medium): While arbitrary file write does not directly enable file reads, a web shell placed via the traversal can subsequently enable full filesystem read access, disclosing configuration files, connection strings, and credentials.
Impact Analysis — Integrity (High): The ability to write arbitrary files to the server filesystem is a direct integrity violation. An attacker can overwrite application files, inject malicious code into CMS templates, or modify configuration to persist access.
Impact Analysis — Availability (Medium): Overwriting critical application or system files can render the CMS instance unavailable.
Prioritization Guidance: The 86.7th percentile EPSS score and KEV listing make this a high-priority patch despite the authentication requirement. Broad staging access grants in enterprise CMS environments and the high impact of arbitrary file write warrant accelerated remediation.
Exploit Maturity
KEV Listing: CISA added CVE-2025-2749 to the Known Exploited Vulnerabilities catalog on April 20, 2026, with a remediation deadline of May 4, 2026. KEV inclusion confirms that the vulnerability has been actively exploited in the wild, not merely that it is theoretically dangerous.
EPSS Context: The EPSS score of 0.03024 (86.7th percentile) places CVE-2025-2749 in the top 13% of all CVEs by predicted exploitation probability. For a vulnerability that requires authentication, this is a notably high percentile, suggesting that either the authentication barrier is easily overcome in practice (e.g., default credentials, compromised accounts, or weak credential policies in CMS environments) or that the exploitation technique is straightforward and widely known.
CMS Exploitation Trends: Enterprise content management systems are frequent targets for web shell deployment, data theft, and supply-chain attacks (modifying public-facing web content). Kentico Xperience is used by organizations in healthcare, financial services, and government sectors, increasing the value of compromised instances to espionage and ransomware actors.
Ransomware: No specific ransomware campaign has been publicly attributed to CVE-2025-2749 at the time of writing. However, arbitrary file write primitives in web applications are commonly used by ransomware precursor malware (initial access brokers) to establish persistent web shells before handing off access to ransomware affiliates.
Public PoC: No public proof-of-concept exploit has been confirmed as of April 24, 2026. Given the 86.7th percentile EPSS and KEV listing, private exploitation tooling is likely already in circulation among threat actors.
Remediation
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Comply with the CISA KEV directive. CISA mandates remediation of CVE-2025-2749 by May 4, 2026. Federal civilian executive branch agencies must meet this deadline; all organizations using Kentico Xperience should adopt it as a best-practice target.
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Apply the Kentico Xperience patch. Upgrade Kentico Xperience to the version that addresses CVE-2025-2749 as specified in Kentico's official security bulletin. Consult the Kentico documentation and DevNet portal for the affected version range and upgrade instructions. Ensure both staging and production environment instances are patched.
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Restrict access to the Staging Sync Server. As an interim mitigation, limit network access to the Staging Sync Server endpoint to only the IP addresses of authorized staging source environments. Apply firewall rules or IIS IP address restrictions to prevent arbitrary clients from reaching the synchronization endpoint. If staging synchronization is not actively in use, consider disabling the Staging Sync Server until the patch is applied.
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Audit staging permissions. Review which user accounts and roles have access to the Staging Sync Server functionality. Apply the principle of least privilege — restrict staging permissions to users who genuinely require them for content workflows. Remove staging access from general content editor roles if the sync feature is not part of their workflow.
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Inspect for signs of exploitation. Review web server logs (IIS or Kestrel) for unusual POST or PUT requests to the Staging Sync Server endpoint, particularly those containing "../" or URL-encoded traversal sequences ("%2e%2e%2f", "%252e%252e%252f"). Scan the web root and application directories for unexpected files, particularly .aspx or .ashx files in locations outside normal CMS deployment paths, which may indicate dropped web shells.
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Harden the application pool identity. Ensure the Kentico Xperience application pool runs with the minimum filesystem permissions required for CMS operation. The application pool identity should not have write access to directories outside the application root and designated upload/temp folders. Consider running the staging sync functionality under a separate, further-restricted identity.
Technical Details
CVE-2025-2749 is a path traversal vulnerability (CWE-22) in the Staging Sync Server component of Kentico Xperience, a .NET-based enterprise CMS built on ASP.NET.
Affected Component — Staging Sync Server: Kentico Xperience includes a Staging module that enables content, objects, and media files to be synchronized between CMS instances — typically from a development or staging environment to production. The Staging Sync Server is the receiver-side HTTP endpoint that accepts synchronization tasks sent from the staging source. Each synchronization task can include file payloads to be written to the target filesystem.
Root Cause — Path Traversal in File Write: The vulnerability arises from insufficient validation or canonicalization of the file path supplied by the synchronization client before the server performs the filesystem write. In a correctly implemented file-write handler, the server should: (1) extract the filename from the request, (2) resolve it against the intended base directory, (3) canonicalize the resulting path, and (4) verify that the canonical path begins with the base directory. CVE-2025-2749 indicates that step (3) or (4) is missing or bypassable, allowing a path parameter containing "../" sequences to resolve to a location outside the intended staging upload directory.
Attack Mechanics: An authenticated attacker with staging permissions sends an HTTP request to the Staging Sync Server endpoint, supplying a file payload and a path parameter crafted as, for example, "../../wwwroot/webshell.aspx" or an equivalent URL-encoded form. The server resolves the path relative to the staging upload directory without checking whether the resolved path escapes the base directory, and writes the attacker's payload to the traversed location. If the traversed path falls within the web root, the attacker can write an ASPX web shell and immediately execute arbitrary server-side code by requesting the shell via HTTP.
Platform Context: Kentico Xperience runs on ASP.NET (Framework or Core) hosted on IIS or Kestrel on Windows Server. The application pool identity in typical IIS deployments often has broad write access to the web application directory tree. This makes path traversal to the web root a viable route to remote code execution without requiring additional privilege escalation on the operating system.
Frequently Asked Questions
Is CVE-2025-2749 being actively exploited?
Yes. CISA added CVE-2025-2749 to the KEV catalog on April 20, 2026, confirming active exploitation in the wild. Organizations running Kentico Xperience with the Staging Sync Server enabled should treat this as an active threat and prioritize immediate patching and access restriction.
What products are affected?
Kentico Xperience (formerly Kentico CMS), a .NET-based enterprise content management system. The vulnerability is specifically in the Staging Sync Server component. Refer to Kentico's official security advisory for the exact affected version numbers.
How do I fix it?
Upgrade Kentico Xperience to the patched version specified in Kentico's security bulletin. As an interim mitigation, restrict network access to the Staging Sync Server endpoint to trusted IP addresses only, and audit which user accounts hold staging permissions. Inspect web server logs and the application file system for signs of web shell deployment.
How severe is it?
CVE-2025-2749 is rated MEDIUM-HIGH severity. Authentication is required, which somewhat limits the exposure, but the 86.7th percentile EPSS score and KEV listing indicate active, real-world exploitation. The ability to write arbitrary files to a web server is a high-impact primitive that frequently leads to remote code execution via web shell deployment, making this vulnerability significantly more dangerous than a typical authenticated issue.
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