# CVE-2026-115638: OpenStack Ironic denial of service via gzip bomb in configdrive

Source: https://junglewise.ai/threats/cve-2026-115638-openstack-ironic-through-39-0-1-allows-a-denial-of-service-via-a  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-23. Updated: 2026-10-23  
License: CC BY 4.0 with a link back

CVE-2026-115638 · Severity: medium · CVSS 4.3 · Published 2026-10-23

OpenStack Ironic is a service that provisions bare metal servers. An authenticated tenant can deploy a specially crafted configuration image (configdrive) containing a gzip bomb—a small file that expands to massive size when decompressed. An attacker could use this to consume all available disk space on the conductor service, rendering it unable to process new deployments and blocking infrastructure provisioning.

Technologies: [OpenStack Ironic](https://junglewise.ai/threats/technologies/ironic). Vendors: [OpenStack](https://junglewise.ai/threats/vendors/openstack).

## Quick answers

**Is CVE-2026-115638 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-115638 being exploited in the wild.

**How severe is CVE-2026-115638?** Medium severity, with a CVSS score of 4.3, published 23 October 2026.

**Which products and versions are affected?** OpenStack Ironic through 39.0.1.

**Is there a fix for CVE-2026-115638?** No fixed version is recorded yet. Restrict provisioning permissions to only trusted tenants and implement disk usage alerting on conductor services to detect abnormal decompression activity. Disable or audit access for any tenant exhibiting signs of malicious configdrive submissions. 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-2026-115638 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-115638?** Check whether you run OpenStack Ironic 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.

## How to fix


Restrict provisioning permissions to only trusted tenants and implement disk usage alerting on conductor services to detect abnormal decompression activity. Disable or audit access for any tenant exhibiting signs of malicious configdrive submissions.

## Technical details

The vulnerability is an uncontrolled decompression of base64-encoded gzip data in the configdrive processing code (ironic/conductor/configdrive_utils.py and ironic/common/kickstart_utils.py). Any authenticated tenant can supply a malicious configdrive to node provisioning APIs; the conductor decompresses it without size limits, allowing a gzip bomb to exhaust disk space. An attacker with provisioning permissions gains the ability to perform denial of service against the conductor infrastructure.

## Affected products

- OpenStack Ironic through 39.0.1

## Timeline

- 2026-10-21: disclosed
- 2026-10-23: advisory

## References

- [https://bugs.launchpad.net/ironic/+bug/2171814](https://bugs.launchpad.net/ironic/+bug/2171814)

## Related threats

- [OpenStack Ironic path injection in Redfish vendor_passthru](https://junglewise.ai/threats/cve-2026-90458-openstack-ironic-before-39-0-1-allows-delete-and-get-via-vendor)
- [OpenStack Ironic authorization bypass in node maintenance setting](https://junglewise.ai/threats/cve-2026-89419-openstack-ironic-before-39-0-1-sometimes-allows-a-user-to-change)
- [OpenStack Ironic credential leakage in HTTP Basic Authentication](https://junglewise.ai/threats/cve-2026-90461-openstack-ironic-credential-leakage-in-http-basic-authentication)
- [OpenStack Ironic autodetect deploy interface cleaning bypass](https://junglewise.ai/threats/cve-2026-74250-openstack-ironic-autodetect-deploy-interface-cleaning-bypass)
- [OpenStack Ironic RBAC bypass in IPMI raw command execution](https://junglewise.ai/threats/cve-2026-54423-openstack-ironic-rbac-bypass-in-ipmi-raw-command-execution)