CVE-2026-49017: CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop') in OpenStack Swift
In OpenStack Swift before 2.36.2 and 2.37.2, s3api middleware enters an infinite loop when processing a truncated aws-chunked PUT request body. The StreamingInput class repeatedly appends an empty buffer and re-reads, causing the proxy-server worker handling the request to become permanently unresponsive with increasing CPU and memory consumption. An authenticated attacker can systematically exhaust all proxy-server workers, resulting in denial of service. The defect was introduced in Swift 2.36.0.
AI Analysis
Technical Summary
This vulnerability involves an infinite loop in the s3api middleware of OpenStack Swift when handling a truncated aws-chunked PUT request body. The StreamingInput class repeatedly appends empty buffers and re-reads, causing the proxy-server worker to hang and consume excessive resources. An authenticated attacker can exploit this to cause denial of service by exhausting proxy-server workers. The defect was introduced in version 2.36.0 and affects versions prior to 2.36.2 and 2.37.2. The service is cloud-hosted, and the vendor manages remediation.
Potential Impact
An authenticated attacker can cause denial of service by triggering an infinite loop in the proxy-server workers, leading to permanent unresponsiveness and resource exhaustion (CPU and memory). This can disrupt availability of the OpenStack Swift service for legitimate users.
Mitigation Recommendations
The vendor manages remediation for this cloud-hosted service. A patch is available as indicated by the patchAvailable flag, and users should ensure their OpenStack Swift deployment is updated to versions 2.36.2 or 2.37.2 or later. Check the vendor advisory for the latest remediation guidance.
CVE-2026-49017: CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop') in OpenStack Swift
Description
In OpenStack Swift before 2.36.2 and 2.37.2, s3api middleware enters an infinite loop when processing a truncated aws-chunked PUT request body. The StreamingInput class repeatedly appends an empty buffer and re-reads, causing the proxy-server worker handling the request to become permanently unresponsive with increasing CPU and memory consumption. An authenticated attacker can systematically exhaust all proxy-server workers, resulting in denial of service. The defect was introduced in Swift 2.36.0.
CVSS v4.0
Score 7.1high
Affected software
pkg:github/openstack/swiftRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability involves an infinite loop in the s3api middleware of OpenStack Swift when handling a truncated aws-chunked PUT request body. The StreamingInput class repeatedly appends empty buffers and re-reads, causing the proxy-server worker to hang and consume excessive resources. An authenticated attacker can exploit this to cause denial of service by exhausting proxy-server workers. The defect was introduced in version 2.36.0 and affects versions prior to 2.36.2 and 2.37.2. The service is cloud-hosted, and the vendor manages remediation.
Potential Impact
An authenticated attacker can cause denial of service by triggering an infinite loop in the proxy-server workers, leading to permanent unresponsiveness and resource exhaustion (CPU and memory). This can disrupt availability of the OpenStack Swift service for legitimate users.
Mitigation Recommendations
The vendor manages remediation for this cloud-hosted service. A patch is available as indicated by the patchAvailable flag, and users should ensure their OpenStack Swift deployment is updated to versions 2.36.2 or 2.37.2 or later. Check the vendor advisory for the latest remediation guidance.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mitre
- Date Reserved
- 2026-05-27T01:57:58.189Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
- Is Cloud Service
- true
Threat ID: 6a16547ae29bf47b5082afdf
Added to database: 05/27/2026, 02:18:34 UTC
Last enriched: 06/03/2026, 20:10:18 UTC
Last updated: 07/11/2026, 19:47:31 UTC
Views: 120
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