CVE-2025-66487 Overview
IBM Aspera Shares versions 1.9.9 through 1.11.0 contain a resource exhaustion vulnerability due to improper rate limiting on email functionality. The application fails to restrict the frequency at which authenticated users can send emails, enabling potential email flooding attacks that could result in denial of service conditions.
Critical Impact
Authenticated users can abuse the email functionality to flood recipients, potentially overwhelming email servers and causing service disruptions.
Affected Products
- IBM Aspera Shares 1.9.9
- IBM Aspera Shares 1.10.x
- IBM Aspera Shares 1.11.0
Discovery Timeline
- April 1, 2026 - CVE CVE-2025-66487 published to NVD
- April 1, 2026 - Last updated in NVD database
Technical Details for CVE-2025-66487
Vulnerability Analysis
This vulnerability is classified under CWE-770 (Allocation of Resources Without Limits or Throttling). The core issue lies in the application's failure to implement proper rate limiting controls on its email sending functionality. Authenticated users can exploit this oversight to send an unlimited number of emails in rapid succession, creating conditions for email flooding attacks.
The vulnerability requires authenticated access to exploit, meaning an attacker must first obtain valid credentials to the IBM Aspera Shares platform. Once authenticated, the attacker can leverage the email functionality without restriction, potentially targeting internal or external recipients with a high volume of messages.
Root Cause
The root cause of CVE-2025-66487 is the absence of throttling mechanisms within the IBM Aspera Shares email sending feature. The application does not implement:
- Request rate limiting per user or session
- Time-based restrictions between email send operations
- Volume caps on the number of emails sent within defined time windows
This design oversight allows authenticated users to make unlimited email requests to the server, which then processes and dispatches each message without checking whether the request frequency is reasonable or within acceptable bounds.
Attack Vector
The attack is network-based and requires low complexity to execute once an attacker has authenticated access. The attacker can craft automated requests to the email sending endpoint, rapidly dispatching large volumes of emails. This can result in:
- Email server resource exhaustion
- Targeted inbox flooding for specific recipients
- Potential blacklisting of the organization's email infrastructure
- Service degradation for legitimate email operations
The vulnerability does not require user interaction beyond the initial authentication, and the scope is unchanged, meaning the impact is contained to the vulnerable component.
Detection Methods for CVE-2025-66487
Indicators of Compromise
- Unusual spikes in outbound email volume from IBM Aspera Shares servers
- Multiple rapid email requests from a single authenticated user session
- Email server logs showing burst patterns of delivery requests from the Aspera Shares application
- Recipient complaints about email flooding originating from your organization
Detection Strategies
- Monitor email server logs for abnormal volume patterns correlated with IBM Aspera Shares
- Implement network-level monitoring to detect high-frequency API calls to email-related endpoints
- Configure alerting for authenticated users exceeding reasonable email send thresholds
- Review application access logs for suspicious automation patterns
Monitoring Recommendations
- Establish baseline metrics for normal email sending behavior within IBM Aspera Shares
- Deploy log aggregation and analysis tools to correlate email activity across infrastructure
- Set up real-time alerts for email volume anomalies tied to specific user accounts
- Integrate email gateway monitoring with SIEM solutions for comprehensive visibility
How to Mitigate CVE-2025-66487
Immediate Actions Required
- Review and restrict email functionality permissions to essential users only
- Implement network-level rate limiting on requests to IBM Aspera Shares email endpoints
- Monitor for any active exploitation attempts in your environment
- Apply vendor patches as soon as they become available
Patch Information
IBM has released information regarding this vulnerability. Organizations running affected versions of IBM Aspera Shares (1.9.9 through 1.11.0) should consult the IBM Support Page for official patch details and remediation guidance.
Workarounds
- Implement proxy-based or WAF rate limiting for email-related API endpoints
- Restrict authenticated access to the email feature to only trusted users
- Configure email gateway policies to throttle outbound messages from the Aspera Shares application
- Temporarily disable email functionality if not critical to operations until patches are applied
# Example: Web server rate limiting configuration (adjust to your environment)
# This is a conceptual example - consult IBM documentation for application-specific controls
# Configure rate limiting at the reverse proxy or load balancer level
# Limit email endpoint requests to 10 per minute per authenticated session
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
