CVE-2026-49017 OpenStack CVE debrief

Who should care

Defenders responsible for OpenStack Swift deployments should assess exposure and prioritize patching due to the potential for denial-of-service attacks. They should verify exposure and apply patches to prevent potential service disruptions. The vulnerability allows for denial-of-service attacks through exhaustion of proxy-server workers, with potential for increased CPU and memory consumption.

Why it matters

CVE-2026-49017 is a high-severity vulnerability in OpenStack Swift that can lead to denial-of-service attacks. Defenders should prioritize verifying exposure and applying patches to prevent potential service disruptions.

• Denial of service through exhaustion of proxy-server workers
• Potential for increased CPU and memory consumption
• Need for verification of exposure and application of patches
• Possible impact on service availability and responsiveness

Technical summary

The vulnerability is caused by the s3api middleware entering an infinite loop when processing a truncated aws-chunked PUT request body. This can lead to proxy-server workers becoming permanently unresponsive with increasing CPU and memory consumption. The defect was introduced in Swift 2.36.0 and can be exploited by authenticated attackers. Defenders should prioritize verifying exposure and applying patches due to the high CVSS score and potential for denial-of-service attacks. The vulnerability allows for denial-of-service attacks through exhaustion of proxy-server workers.

Defensive priority

Defenders should prioritize verifying exposure and applying patches due to the high CVSS score and potential for denial-of-service attacks.

Recommended defensive actions

• Verify exposure by checking OpenStack Swift versions and configurations
• Apply patches or updates to affected versions
• Monitor proxy-server worker responsiveness and resource consumption
• Implement compensating controls to limit authenticated user access
• Review relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The vulnerability was introduced in Swift 2.36.0 and can be exploited by authenticated attackers. The CVE record and NVD entry provide details on the affected versions and potential impact. Defenders should verify exposure and apply patches to prevent potential service disruptions. The vulnerability allows for denial-of-service attacks through exhaustion of proxy-server workers, with potential for increased CPU and memory consumption.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.