# CVE-2026-11537: IBM WebSphere Application Server information disclosure via FileTransfer servlet

Source: https://junglewise.ai/threats/cve-2026-11537-ibm-websphere-application-server-9-0-and-8-5-could-allow-a-remote  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-18. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-11537 · Severity: medium · CVSS 4.3 · Published 2026-09-18

IBM WebSphere Application Server is a Java application platform used to host enterprise web applications and services. A remote attacker can exploit a vulnerability in the FileTransfer servlet to obtain sensitive information about the server's file system, potentially exposing configuration files, source code, or other confidential data.

Technologies: [IBM WebSphere Application Server](https://junglewise.ai/threats/technologies/websphere-application-server). Vendors: [IBM](https://junglewise.ai/threats/vendors/ibm).

## Quick answers

**Is CVE-2026-11537 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-11537 being exploited in the wild.

**How severe is CVE-2026-11537?** Medium severity, with a CVSS score of 4.3, published 18 September 2026.

**Which products and versions are affected?** IBM WebSphere Application Server 8.5 before 8.5.5.31, 9.0 before 9.0.5.29.

**Is there a fix for CVE-2026-11537?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-11537 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-11537?** Check whether you run IBM WebSphere Application Server at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability exists in the FileTransfer servlet of IBM WebSphere Application Server versions 8.5 and 9.0 prior to the patched versions (8.5.5.31 and 9.0.5.29). A remote attacker can leverage improper access controls or input validation in this servlet to read files from the server's file system. The attack requires network access to the vulnerable servlet and no authentication is specified as required.

## Affected products

- IBM WebSphere Application Server 8.5 before 8.5.5.31, 9.0 before 9.0.5.29

## Timeline

- 2026-09-18: disclosed

## References

- [https://www.ibm.com/support/pages/node/7286610](https://www.ibm.com/support/pages/node/7286610)

## Related threats

- [IBM WebSphere Application Server insecure deserialization in messaging](https://junglewise.ai/threats/cve-2026-105442-ibm-websphere-application-server-8-5-and-9-0-and-ibm-websphere)
- [IBM WebSphere Application Server cryptographic signature verification bypass](https://junglewise.ai/threats/cve-2026-101294-ibm-websphere-application-server-liberty-17-0-0-3-through-26-0-0)
- [IBM WebSphere Application Server authorization bypass in authentication](https://junglewise.ai/threats/cve-2026-95680-ibm-websphere-application-server-8-5-and-9-0-could-allow-an)
- [IBM WebSphere Application Server authentication bypass in CSIv2](https://junglewise.ai/threats/cve-2026-93907-ibm-websphere-application-server-8-5-and-9-0-could-allow-a-remote)
- [IBM WebSphere Application Server denial of service via resource consumption](https://junglewise.ai/threats/cve-2026-103499-ibm-websphere-application-server-liberty-17-0-0-3-through-26-0-0)