dbcve.org
Infinite LoopWeakness · CWE-835

CVE-2026-49017

HIGH · 7.1 CVSS v4.0 Published 2026-05-27
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
77/100
Remediation priority · High
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

In OpenStack Swift s3api middleware, the StreamingInput class enters an infinite loop when processing a truncated aws-chunked PUT request body. The class repeatedly appends an empty buffer and re-reads, causing the proxy-server worker to become permanently unresponsive with increasing CPU and memory consumption. An authenticated attacker can exhaust all proxy-server workers, resulting in denial of service.

MitigationUpgrade OpenStack Swift to version 2.36.2, 2.37.2, or later. Alternatively, implement rate limiting or request size validation on the s3api endpoint to limit exposure to authenticated attackers.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
Authentication
X
User interaction
None
Scope
X

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify Swift installation and version
    Run 'swift --version' or check the installed swift-common package version via package manager (dpkg -l swift-common or rpm -qi swift-common)
    Affected if The installed version is prior to 2.36.2 or 2.37.2 (the fixed releases)
  2. Confirm s3api middleware is enabled
    Inspect the Swift proxy-server.conf file (typically in /etc/swift/) and look for 's3api' in the pipeline or filter list under [pipeline:main]
    Affected if The s3api middleware is present in the active proxy-server pipeline configuration
  3. Check for aws-chunked request handling capability
    Verify the s3api middleware is configured to handle S3 signature version 4 requests which use aws-chunked encoding. Check proxy-server.conf for s3api-related filter sections.
    Affected if The s3api endpoint accepts authenticated S3-style requests using AWS Signature Version 4
  4. Identify proxy-server worker count
    Check the proxy-server.conf for 'workers' or 'concurrency' settings under the [proxy-server] section
    Affected if The proxy-server is running with workers configured (vulnerable to worker exhaustion)
  5. Review recent proxy-server crash or hang incidents
    Examine system logs (/var/log/swift/proxy.log) for signs of stuck workers, high CPU usage, or memory growth associated with PUT requests using aws-chunked transfer encoding
    Affected if Logs show proxy-server workers becoming unresponsive after processing PUT requests with aws-chunked body

A user is affected if they are running a Swift version before 2.36.2/2.37.2 with the s3api middleware enabled and processing authenticated S3 API requests.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade OpenStack Swift to version 2.36.2, 2.37.2, or later. Alternatively, implement rate limiting or request size validation on the s3api endpoint to limit exposure to authenticated attackers.

Recommended fix High confidence

Upgrade to Swift 2.36.2 or 2.37.2 (either branch)

  1. Identify the currently deployed OpenStack Swift version using 'swift --version' or checking the package manager
  2. If running Swift 2.36.0 or 2.36.1, upgrade to version 2.36.2
  3. If running Swift 2.37.0 or 2.37.1, upgrade to version 2.37.2
  4. If running a version earlier than 2.36.0, upgrade to at least 2.36.2 or 2.37.2
  5. After upgrade, restart all proxy-server workers to clear any potentially stuck processes: swift-proxy-server restart or systemctl restart swift-proxy
Caveat Review release notes for 2.36.2 and 2.37.2 to check for API compatibility changes before upgrading production systems

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,080
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-49017 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data