5.3

CVE-2021-21419: Improper Handling of Highly Compressed Data (Data Amplification) and Memory Allocation with Excessive Size Value in eventlet

Modified
AliasesMGASA-2021-0266GHSA-9p9m-jm8w-94p2PYSEC-2021-12
Published 07-05-2021Last modified 03-08-2024

Vulnerability summary

CVE-2021-21419 is a medium (CVSS 5.3) Uncontrolled Resource Consumption vulnerability in eventlet. EPSS estimates a 1.79% chance of exploitation in the next 30 days, higher than 78.4% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.3, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.3/10
010
Medium · v3.1 (CVE.org)
EPSS score
1.79%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 3 · Related 2
RHSA-2021:2437SUSE-SU-2021:2554-1SUSE-SU-2021:3729-1

Timeline

  1. 07-05-2021
    PublishedVulnerability first disclosed.
  2. 03-08-2024
    Last modifiedVulnerability information updated.

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.

CVSS metrics

8 scores · 6 sources · 3 versions

EPSS trend

Probability

1.79%

Chance of exploitation in the next 30 days

Percentile

78%

Versus all other CVEs

30-day change

No change 0.00 pp

From 1.79% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Mageia2 products
  • python-eventlet< 0.24.1-1.1.mga7
  • python-eventlet< 0.31.0-1.mga8
Redhat2 products
  • python-eventlet< 0:0.25.2-5.el8ost.1
  • python3-eventlet< 0:0.25.2-5.el8ost.1
Debian1 product
  • python-eventlet< 0.26.1-7
Eventlet1 product
Fedoraproject1 product
PyPI1 product
  • eventlet≥ 0.10, < 0.31.0 | ≥ 0.10.0, < 0.31.0
Ubuntu1 product
  • python-eventlet< 0.25.1-2ubuntu1.1

7 vendors · 9 products

References

21 links
Show all 21 references