CVE-2025-36034: IBM InfoSphere Information Disclosure Flaw

CVE-2025-36034 Overview

CVE-2025-36034 affects IBM InfoSphere DataStage Flow Designer within IBM InfoSphere Information Server 11.7. The component transmits sensitive user information in API requests as cleartext. An attacker positioned on the network path can intercept these requests using man-in-the-middle (MITM) techniques and read the exposed data. The weakness is classified under [CWE-319]: Cleartext Transmission of Sensitive Information. IBM has published a support advisory addressing the flaw.

Critical Impact
A network-adjacent attacker who intercepts DataStage Flow Designer API traffic can harvest sensitive user information transmitted without encryption, enabling downstream credential abuse or reconnaissance against the InfoSphere environment.

Affected Products

IBM InfoSphere Information Server 11.7
IBM InfoSphere DataStage Flow Designer (component)
CPE: cpe:2.3:a:ibm:infosphere_information_server:11.7

Discovery Timeline

2025-06-26 - CVE-2025-36034 published to the National Vulnerability Database (NVD)
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-36034

Vulnerability Analysis

The vulnerability resides in how IBM InfoSphere DataStage Flow Designer communicates with backend services. API requests carry sensitive user information without applying transport-layer encryption. This leaves the data readable to any party observing the network path between the client and server.

Exploitation requires a network position that permits traffic interception. Attackers on the same broadcast domain, compromised network devices, or upstream infrastructure operators satisfy this precondition. The vulnerability does not require authentication or user interaction, but the attack complexity is elevated because the attacker must first achieve a suitable interception vantage point.

Successful interception yields confidentiality loss. The advisory does not indicate integrity or availability impact from this weakness alone. Harvested user information can be reused to authenticate to the Information Server console, pivot into connected data sources, or map internal identities for follow-on operations.

Root Cause

The root cause is a missing or improperly enforced use of encrypted transport for API traffic generated by the Flow Designer client. When the client issues requests, sensitive user attributes travel in cleartext rather than through a TLS-protected channel with server certificate validation. This is a classic [CWE-319] pattern where security-relevant data is emitted without cryptographic protection.

Attack Vector

The attack vector is network-based. An adversary conducts ARP spoofing, DNS redirection, rogue Wi-Fi access, transparent proxying, or compromise of intermediate routers to sit between the DataStage Flow Designer client and the Information Server. The adversary then passively captures HTTP payloads or actively terminates and relays connections to extract user information from API requests. No exploit tooling has been published, and the vulnerability is not listed on the CISA Known Exploited Vulnerabilities catalog.

No verified exploit code is available. Refer to the IBM Support advisory for vendor-supplied technical detail.

Detection Methods for CVE-2025-36034

Indicators of Compromise

Unencrypted HTTP traffic originating from DataStage Flow Designer clients on ports typically expected to carry TLS.
Unexpected ARP table changes or duplicate MAC address entries on network segments hosting Information Server clients.
Presence of promiscuous-mode interfaces or unauthorized packet capture processes on hosts adjacent to InfoSphere traffic.

Detection Strategies

Inspect network flows between Flow Designer clients and Information Server nodes for plaintext API payloads containing user identifiers or tokens.
Correlate authentication events in InfoSphere logs with source IP addresses to spot logins originating from atypical hosts after suspected interception.
Deploy TLS inspection policies that flag or block cleartext requests to Information Server API endpoints.

Monitoring Recommendations

Enable and centralize InfoSphere Information Server audit logs, including authentication and API access events.
Alert on IDS/IPS signatures for ARP poisoning, DHCP spoofing, and rogue gateway advertisements on segments serving DataStage users.
Track certificate errors and downgrade attempts reported by InfoSphere clients as potential MITM indicators.

How to Mitigate CVE-2025-36034

Immediate Actions Required

Apply the fix referenced in the IBM Support advisory for CVE-2025-36034.
Restrict DataStage Flow Designer usage to trusted network segments until patching is complete.
Rotate credentials and API tokens for users who accessed Flow Designer over untrusted networks prior to remediation.

Patch Information

IBM has published remediation guidance for IBM InfoSphere Information Server 11.7 through its support portal. Administrators should review the IBM Support Page for the exact fix pack, iFix identifier, and installation prerequisites applicable to their deployment.

Workarounds

Enforce TLS at the network layer using a reverse proxy or service mesh in front of Information Server endpoints, and reject cleartext connections.
Require VPN or IPsec tunnels for all client-to-Information-Server communication until the vendor patch is applied.
Segment InfoSphere infrastructure into dedicated VLANs with strict access control lists to limit MITM opportunities.

bash

# Example: block cleartext HTTP to the InfoSphere API host at the perimeter
iptables -A FORWARD -p tcp -d <infosphere_server_ip> --dport 80 -j DROP
iptables -A FORWARD -p tcp -d <infosphere_server_ip> --dport 443 -m state --state NEW,ESTABLISHED -j ACCEPT