CVE-2026-7673 Overview
CVE-2026-7673 is an unrestricted file upload vulnerability affecting crmeb_java versions up to 1.3.4. The flaw resides in the UploadServiceImpl.java file located at crmeb/crmeb-service/src/main/java/com/zbkj/service/service/impl/UploadServiceImpl.java, part of the Admin Upload component. Manipulation of the model argument allows authenticated administrators to bypass upload restrictions. The vulnerability is categorized under [CWE-284] (Improper Access Control) and is exploitable remotely over the network. A public exploit exists, and the vendor did not respond to disclosure attempts.
Critical Impact
Authenticated administrators can upload arbitrary files to the server, potentially leading to malicious content placement and follow-on compromise of the application.
Affected Products
- crmeb_java versions up to and including 1.3.4
- Admin Upload component (UploadServiceImpl.java)
- Deployments exposing the administrative upload interface to the network
Discovery Timeline
- 2026-05-03 - CVE-2026-7673 published to NVD
- 2026-05-04 - Last updated in NVD database
Technical Details for CVE-2026-7673
Vulnerability Analysis
The vulnerability stems from improper access control on the file upload routine within the crmeb_java administrative interface. The UploadServiceImpl.java class processes upload requests and accepts a user-controlled model parameter. Manipulating this parameter circumvents the upload validation logic, permitting files outside the intended type or location scope to be written to the server.
Exploitation requires authenticated access with high privileges, which limits broad opportunistic attacks. However, once an attacker obtains administrator credentials through phishing, credential reuse, or session theft, the upload restriction can be bypassed remotely without user interaction. The exploit code has been published, lowering the barrier for adversaries to weaponize the flaw.
Impact remains constrained to limited confidentiality, integrity, and availability effects on the host application. Refer to the VulDB Vulnerability #360826 entry and the Feishu technical document for additional technical context.
Root Cause
The root cause is insufficient validation of the model argument inside UploadServiceImpl.java. The service trusts client-supplied input to determine upload destination or accepted content type. Without strict allow-listing of file types, MIME types, and target paths, the upload handler accepts content that should be rejected.
Attack Vector
The attack vector is network-based. An authenticated administrator sends a crafted upload request manipulating the model parameter to the vulnerable endpoint. The server processes the upload without enforcing proper restrictions, writing the attacker-supplied file to the application's storage. The privilege requirement is high, since access to the Admin Upload component requires administrator authentication.
No verified exploit code is reproduced here. See the VulDB submission #800684 for additional references.
Detection Methods for CVE-2026-7673
Indicators of Compromise
- Unexpected files appearing in the upload directories managed by crmeb_java
- Administrative upload requests containing unusual or unexpected model parameter values
- Web server logs showing successful uploads of file extensions outside the documented allow list
Detection Strategies
- Inspect HTTP request logs for POST requests to the Admin Upload endpoint and correlate the model parameter against expected values
- Hash and compare uploaded artifacts against known good baselines to identify unauthorized files
- Alert on administrator session activity that deviates from typical upload patterns, such as off-hours uploads or unusual source IP addresses
Monitoring Recommendations
- Enable verbose audit logging on the crmeb_java administrative console and forward logs to a centralized SIEM
- Monitor file system changes within application upload directories using file integrity monitoring
- Track administrator authentication events and flag logins from anomalous geolocations or devices
How to Mitigate CVE-2026-7673
Immediate Actions Required
- Restrict network access to the crmeb_java administrative interface using firewall rules or VPN-only access
- Rotate administrator credentials and enforce multi-factor authentication on all privileged accounts
- Review upload directories for unauthorized files and remove any suspicious artifacts
Patch Information
The vendor was contacted prior to disclosure but did not respond. No official patch is referenced in the published advisory. Organizations operating crmeb_java versions up to 1.3.4 should monitor the VulDB Vulnerability #360826 entry and the project repository for updates.
Workarounds
- Implement a reverse proxy rule that validates the model parameter against an allow list before forwarding requests to the upload endpoint
- Enforce server-side file type and extension validation at the web server or WAF layer to reject non-permitted content
- Disable the Admin Upload functionality if it is not required for business operations
- Apply strict file system permissions on upload directories to prevent execution of uploaded content
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
