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TI-2021-04517 Aliases CVE-2021-21419GHSA-9p9m-jm8w-94p2

Uncontrolled resource consumption in eventlet

Priority LOW 28CWE-400Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · Low
Fix status
Partial Red Hat: 2 fixed, 3 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-400.

Summary

Eventlet is a concurrent networking library for Python. A websocket peer may exhaust memory on Eventlet side by sending very large websocket frames. Malicious peer may exhaust memory on Eventlet side by sending highly compressed data frame. A patch in version 0.31.0 restricts websocket frame to reasonable limits. As a workaround, restricting memory usage via OS limits would help against overall machine exhaustion, but there is no workaround to protect Eventlet process.

Why it matters now

EPSS 0.01792 78th percentileScored 2026-11-07
Fix Partial eventlet (eventlet): 0.31.0eventlet (PyPI): 0.31.0Red Hat: 2 advisoriesRed Hat: 2 fixed, 3 without a fix

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
eventleteventlet0.10 to before 0.31.00.31.0Patch availableCNA
—eventlet (PyPI)0.10 to before 0.31.00.31.0Patch availableGHSA-9p9m-jm8w-94p2
  • eventlet Vendoreventlet Affected 0.10 to before 0.31.0 Fixed in 0.31.0 Patch available CNA
  • eventlet (PyPI) Vendor— Affected 0.10 to before 0.31.0 Fixed in 0.31.0 Patch available GHSA-9p9m-jm8w-94p2

CPE configurations NVD · 3

CPEVersionsRoleVendor
cpe:2.3:a:eventlet:eventlet:*:*:*:*:*:*:*:*0.10 to before 0.31.0Vulnerableeventlet
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*33VulnerableFedoraproject
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*34VulnerableFedoraproject
  • cpe:2.3:a:eventlet:eventlet:*:*:*:*:*:*:*:* Versions 0.10 to before 0.31.0 Vulnerable ·eventlet
  • cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* Versions 33 Vulnerable ·Fedoraproject
  • cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* Versions 34 Vulnerable ·Fedoraproject

Remediation

  • Fix · CNA eventlet (eventlet) Fixed in 0.31.0
  • Fix · GHSA-9p9m-jm8w-94p2 eventlet (PyPI) Fixed in 0.31.0 Advisory →

Red Hat 2 advisories

  • RHSA-2021:5071 Released 2021-12-09 · Red Hat rating Moderate
    Red Hat OpenStack Platform 16.1 (python-eventlet) security update
    • Red Hat OpenStack Platform 16.1 python-eventlet-0.25.2-5.el8ost.1, python3-eventlet-0.25.2-5.el8ost.1
  • RHSA-2021:2437 Released 2021-07-27 · Red Hat rating Moderate
    OpenShift Container Platform 4.8.2 packages and security update
    • Red Hat OpenShift Container Platform 4.8 afterburn-5.0.0-1.rhaos4.8.el8, atomic-openshift-service-idler-4.8.0-202106281541.p0.git.39cfc66.assembly.stream.el8, butane-0.12.1-1.rhaos4.8.el8 +47

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat OpenStack Platform 10 (Newton)AffectedNo fix planned: Out of support scope
Red Hat OpenStack Platform 13 (Queens)AffectedNo fix planned: Will not fix
Red Hat Storage 3AffectedNo fix planned: Will not fix
Red Hat OpenShift Container Platform 4.8Fixed RHSA-2021:2437
Red Hat OpenStack Platform 16.1Fixed RHSA-2021:5071
Not affected: 1 product
  • Red Hat OpenShift Container Platform 4.8

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-21419
  2. 2026-10-03 Alias added: GHSA-9p9m-jm8w-94p2

References

Advisory 4

Other 5

  • TI-2023-13855 eventlet before 0.35.2, as used in dnspython before 2.6.0, allows remote attackers to… CVSS 3.1HIGH 7.0
  • TI-2025-35911 Eventlet affected by HTTP request smuggling in unparsed trailers CVSS 4.0MEDIUM 6.3

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences