OpenStack Swift: s3api middleware enters an infinite loop when processing a truncated aws-chunked PUT request body
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.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | swift | >= 2.36.0, <= 2.36.1, >= 2.37.0, <= 2.37.1 | no fix |
References
- https://nvd.nist.gov/vuln/detail/CVE-2026-49017
- https://bugs.launchpad.net/bugs/2152205
- https://github.com/openstack/swift
- https://review.opendev.org/c/openstack/swift/+/987957
- https://review.opendev.org/c/openstack/swift/+/988093
- http://www.openwall.com/lists/oss-security/2026/05/27/9
- http://www.openwall.com/lists/oss-security/2026/06/02/6
- https://pypi.org/project/swift
- https://github.com/advisories/GHSA-g7jq-j257-rww2
- CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L- Weakness (CWE)
CWE-835- Platform
- Python (PyPI)
- Package
swift- Disclosed
- 27.05.2026
- Updated
- 11.10.2026 14:18
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-3080 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-g7jq-j257-rww2 - CC BY 4.0
Vulnerability history: swift
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 14
- First → latest
- 01.2014 06.2026
- Without a fix
- 1
- Exploited in attacks
- 0
Severity breakdown
- Critical 1
- High 5
- Medium 7
- Low 1
Disclosures per year
- 2017: 0
- 2018: 0
- 2019: 0
- 2020: 0
- 2021: 1
- 2022: 9
- 2023: 1
- 2024: 0
- 2025: 0
- 2026: 2
earlier: 1
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OpenStack Swift: s3api middleware enters an infinite loop when processing a truncated aws-chunked PUT request body this entry
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