CVE-2021-21419

Improper Handling of Highly Compressed Data (Data Amplification) and Memory Allocation with Excessive Size Value in eventlet

MEDIUM
5.3
CVSS Score
Published: May 7, 2021 at 02:30 PM UTC
Updated: June 17, 2026 at 03:35 AM UTC
2 products affected across 2 vendorsFedoraEventlet

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Severity
MEDIUM5.3
Exploit prediction
EPSS 2%

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 0.31.00.10 ≤ v < 0.31.0
Affected range stops below 0.31.0, so it looks safe — our inference, not a vendor statement

CVSS

5.3MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
LOW
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-400

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