CVE-2026-13275: IBM MQ Managed File Transfer XXE Vulnerability

CVE-2026-13275 Overview

CVE-2026-13275 is an XML External Entity (XXE) injection vulnerability in IBM MQ Managed File Transfer. The flaw resides in reply message processing and allows an authenticated attacker to read arbitrary files or perform server-side request forgery (SSRF) against internal systems. The vulnerability is tracked under CWE-611: Improper Restriction of XML External Entity Reference.

Critical Impact
An authenticated remote attacker can exfiltrate sensitive files from the MQ server host and pivot to internal network resources through SSRF, exposing configuration data, credentials, and internal services.

Affected Products

IBM MQ Managed File Transfer 9.1.0.0 through 9.1.0.37 LTS
IBM MQ Managed File Transfer 9.2.0.0 through 9.2.0.43 LTS, 9.3.0.0 through 9.3.0.41 LTS, and 9.3.0.0 through 9.3.5.1 CD
IBM MQ Managed File Transfer 9.4.0.0 through 9.4.0.25 LTS, 9.4.0.0 through 9.4.5.1 CD, and 10.0.0.0

Discovery Timeline

2026-09-14 - CVE-2026-13275 published to NVD
2026-09-16 - Last updated in NVD database

Technical Details for CVE-2026-13275

Vulnerability Analysis

The vulnerability affects the reply message processing path within IBM MQ Managed File Transfer (MFT). MFT exchanges XML-formatted control and status messages between agents to coordinate file transfers. When a reply message is parsed, the underlying XML parser resolves external entity references without adequate restrictions.

An authenticated attacker who can submit crafted reply messages triggers the parser to fetch content referenced by external entities. The parser then embeds that content in the processed document or issues outbound requests. This enables both local file disclosure and SSRF against systems reachable from the MQ server.

Exploitation requires valid credentials with the ability to submit messages to the MFT agent queue. Confidentiality impact is high because the parser runs with the privileges of the MQ user and can access files readable by that account.

Root Cause

The root cause is an XML parser configured to resolve external entities and external DTDs by default. Under CWE-611, the parser fails to disable DOCTYPE declarations, external general entities, and external parameter entities before processing untrusted XML content received in reply messages.

Attack Vector

The attacker submits a malicious reply message containing a crafted XML payload with an external entity reference. The entity references either a local file URI, such as file:///etc/passwd or an MQ configuration file, or a remote URI targeting an internal HTTP service. When the MFT agent parses the reply, the parser dereferences the entity and either returns file contents in an error or response channel or issues an outbound network request.

Refer to the IBM Support Page for vendor-supplied technical details on the vulnerable message processing path.

Detection Methods for CVE-2026-13275

Indicators of Compromise

Unexpected outbound network connections originating from MFT agent processes to internal IP ranges or external hosts.
MQ or MFT log entries referencing XML parsing errors, external entity resolution failures, or DOCTYPE declarations in reply messages.
File access events showing MFT processes reading sensitive files such as /etc/passwd, /etc/shadow, or MQ keystore files outside normal operation.

Detection Strategies

Inspect MFT reply message payloads at the queue or broker layer for <!DOCTYPE, <!ENTITY, or SYSTEM keywords that indicate XXE attempts.
Correlate authentication events against MFT agents with subsequent anomalous XML parser errors in agent logs.
Baseline outbound network traffic from MQ hosts and alert on new destinations, particularly connections to cloud metadata endpoints such as 169.254.169.254.

Monitoring Recommendations

Forward IBM MQ error logs, MFT agent event logs, and host process telemetry to a centralized SIEM for correlation and retention.
Enable file integrity and file access monitoring on MQ configuration directories, keystores, and credential stores.
Monitor MFT service accounts for unusual command execution or file read patterns using endpoint detection and response tooling.

How to Mitigate CVE-2026-13275

Immediate Actions Required

Apply the IBM-supplied fix or interim fix documented on the IBM Support Page to all affected MQ Managed File Transfer installations.
Restrict MFT agent access to authenticated users with a validated business need and rotate credentials for accounts exposed to untrusted networks.
Segment MQ hosts from sensitive internal services to limit SSRF impact until patches are deployed.

Patch Information

IBM has published remediation guidance on the IBM Support Page covering the affected 9.1, 9.2, 9.3, 9.4 LTS and CD streams and 10.0.0.0. Administrators should upgrade to a fixed release or apply the interim fix identified for each affected version.

Workarounds

Enforce network-level restrictions on outbound traffic from MQ hosts, blocking access to internal management interfaces and cloud metadata services.
Deploy a message inspection or gateway layer that rejects MFT XML payloads containing DOCTYPE or external entity declarations.
Reduce the file system privileges of the MQ service account so that arbitrary file reads through the parser return no sensitive content.

bash

# Example egress restriction using iptables on an MQ host
iptables -A OUTPUT -m owner --uid-owner mqm -d 169.254.169.254 -j DROP
iptables -A OUTPUT -m owner --uid-owner mqm -d 10.0.0.0/8 -p tcp --dport 22 -j DROP
iptables -A OUTPUT -m owner --uid-owner mqm -d 127.0.0.0/8 ! -o lo -j DROP