# CVE-2026-17440: IBM App Connect Enterprise uncontrolled recursion denial of service

Source: https://junglewise.ai/threats/cve-2026-17440-ibm-app-connect-enterprise-uncontrolled-recursion-denial-of  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-04. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-17440 · Severity: medium · CVSS 5.5 · Published 2026-09-04

IBM App Connect Enterprise is an integration platform used to connect business applications and services. A vulnerability in the product allows a local attacker to trigger excessive recursion, causing the application to crash and become unavailable. This can disrupt critical business operations that depend on application integration.

Technologies: [IBM App Connect Enterprise](https://junglewise.ai/threats/technologies/app-connect-enterprise), [IBM Integration Bus for z/OS](https://junglewise.ai/threats/technologies/integration-bus-for-z-os). Vendors: [IBM](https://junglewise.ai/threats/vendors/ibm).

## Quick answers

**Is CVE-2026-17440 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-17440 being exploited in the wild.

**How severe is CVE-2026-17440?** Medium severity, with a CVSS score of 5.5, published 4 September 2026.

**Which products and versions are affected?** IBM App Connect Enterprise 12.0.1.0 through 12.0.12.28, 13.0.1.0 through 13.0.8.1; IBM Integration Bus for z/OS 10.1.0.0 through 10.1.0.7.

**Is there a fix for CVE-2026-17440?** A patch was published on 2026-09-04: APAR IT49773 released in App Connect Enterprise 13.0.8.2 and 12.0.12.29; interim fix available for Integration Bus for z/OS Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-17440 attacked?** It is attacked with local access, in a hosted service.

**Am I affected by CVE-2026-17440?** Check whether you run IBM App Connect Enterprise or IBM Integration Bus for z/OS 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 is an uncontrolled recursion flaw (CWE-674) in IBM App Connect Enterprise versions 12.0.1.0–12.0.12.28 and 13.0.1.0–13.0.8.1, as well as IBM Integration Bus for z/OS 10.1.0.0–10.1.0.7. A local attacker with limited privileges can trigger the recursion condition without user interaction, causing a denial of service by exhausting stack resources. The CVSS 3.1 vector (AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H) indicates local access and low privileges are required; the impact is high availability disruption. Patches are available: APAR IT49773 in App Connect Enterprise 13.0.8.2 and 12.0.12.29, and an interim fix for Integration Bus for z/OS 10.1.0.7.

## Affected products

- IBM App Connect Enterprise 12.0.1.0 through 12.0.12.28, 13.0.1.0 through 13.0.8.1
- IBM Integration Bus for z/OS 10.1.0.0 through 10.1.0.7

## Timeline

- 2026-09-04: disclosed: CVE-2026-17440 published in NVD
- 2026-09-04: patched: APAR IT49773 released in App Connect Enterprise 13.0.8.2 and 12.0.12.29; interim fix available for Integration Bus for z/OS

## References

- [https://www.ibm.com/support/pages/node/7286372](https://www.ibm.com/support/pages/node/7286372)

## Related threats

- [IBM App Connect Enterprise HTML injection in web UI](https://junglewise.ai/threats/cve-2026-18196-ibm-app-connect-enterprise-13-0-1-0-through-13-0-8-2-and-12-0-1-0)
- [IBM App Connect Enterprise content spoofing in error messages](https://junglewise.ai/threats/cve-2026-18195-ibm-app-connect-enterprise-13-0-1-0-through-13-0-8-2-and-12-0-1-0)
- [IBM App Connect Enterprise broken access control in REST API](https://junglewise.ai/threats/cve-2026-18093-ibm-app-connect-enterprise-13-0-1-0-through-13-0-8-2-could-allow)
- [IBM App Connect Enterprise arbitrary file write in archive extraction](https://junglewise.ai/threats/cve-2026-17437-ibm-app-connect-enterprise-13-0-1-0-through-13-0-8-2-and-12-0-1-0)
- [IBM App Connect Enterprise binding to unrestricted IP address](https://junglewise.ai/threats/cve-2026-92559-ibm-app-connect-enterprise-13-0-1-0-through-13-0-8-2-could-allow)