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Fencer Vulns
medium 6.5

CVE-2026-49017 json

OpenStack Swift: s3api middleware enters an infinite loop when processing a truncated aws-chunked PUT request body

published 2026-05-27 5 mo ago modified 2026-09-24 45 d ago also GHSA-g7jq-j257-rww2 , PYSEC-2026-3080 , EUVD-2026-32040

cvss
6.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 29%
public exploits
0
none known

Summary

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.

Patch / fix

  • OpenStack Swift 2.35.3, 2.36.2, 2.37.2
  • swift Debian 13 2.35.1-0+deb13u2
  • swift Debian 14 2.37.1-4

debian advisories DEBIAN-CVE-2026-49017

  • swift Ubuntu 26.04 LTS 2.37.1-0ubuntu2.1

ubuntu advisories UBUNTU-CVE-2026-49017

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-49017 updated cvss 6.5

openstack-swift: OpenStack Swift: Denial of Service via truncated aws-chunked PUT request

  • Red Hat OpenStack Platform 16.2 python3-swift, openstack-swift, openstack-swift-proxy, openstack-swift-object, openstack-swift-account, openstack-swift-container Red Hat OpenStack Platform 17.1 python3-swift, openstack-swift, openstack-swift-proxy, openstack-swift-object, openstack-swift-account, openstack-swift-container Red Hat OpenStack Platform 18.0 openstack-swift
    affected: workaround, no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
5 mo ago

Exploit prediction

0.36% chance of exploitation in the next 30 days, higher than 29% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 7.1 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
CNA 4.0 7.1 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
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
pypi swift
>=2.36.0, <=2.36.1
>=2.37.0, <=2.37.1
 no fix listed

Affected products

  • OpenStack Swift

Classification

Weakness
  • CWE-835 Loop with Unreachable Exit Condition

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.