Skip to content
Fencer Vulns
high 7.5

CVE-2018-1000518 json

websockets is vulnerable to denial of service by memory exhaustion

published 2018-06-26 8 y ago modified 2026-06-17 4 mo ago also GHSA-6g87-ff9q-v847 , PYSEC-2018-79 , EUVD-2018-0146

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.8%
EPSS 1.8% chance of exploitation in 30 days, percentile 78%
public exploits
0
none known

Summary

aaugustin websockets version 4 contains a CWE-409: Improper Handling of Highly Compressed Data (Data Amplification) vulnerability in Servers and clients, unless configured with compression=None that can result in Denial of Service by memory exhaustion. This attack appear to be exploitable via Sending a specially crafted frame on an established connection. This vulnerability appears to have been fixed in 5.

Patch / fix

  • pypi websockets 5.0
  • protobuf SLE Module for Public Cloud 15 SP1, SLE Installer Updates 15 SP1, SLES for SAP 15 SP1 +2 more 3.9.2-150100.8.3.3
  • python-psutil SLE Module for Public Cloud 15 SP1, Enterprise Storage 7, SLES for SAP 15 SP2 +5 more 5.9.1-150100.6.6.3
  • python-requests SLE Module for Public Cloud 15 SP1, Enterprise Storage 7, SLES for SAP 15 SP2 +5 more 2.25.1-150100.6.13.3
  • grpc SLE Module for Public Cloud 15 SP1 1.25.0-150100.3.3.3
  • python-avro SLE Module for Public Cloud 15 SP4, SLE Module for Public Cloud 15 SP3, SLE Module for Public Cloud 15 SP2 +1 more 1.11.0-150100.3.3.3
  • python-knack SLE Module for Public Cloud 15 SP5, SLE Module for Public Cloud 15 SP4, SLE Module for Public Cloud 15 SP3 +3 more 0.9.0-150100.3.7.3
  • python-pytest SLE Module for Public Cloud 15 SP2, SLE Module for Public Cloud 15 SP1 3.10.1-150000.7.5.1
  • azure-cli-core SLE Module for Public Cloud 15 SP5, SLE Module for Public Cloud 15 SP4, SLE Module for Public Cloud 15 SP3 +3 more 2.17.1-150100.6.18.1

suse advisories SUSE-SU-2023:2783-2SUSE-SU-2023:2783-1

  • python-websockets openSUSE Tumbleweed 16.0-2.1
  • python-websockets openSUSE Tumbleweed 12.0-2.6
  • python-websockets openSUSE Tumbleweed 9.1-2.1

opensuse advisories openSUSE-SU-2026:11240-1openSUSE-SU-2024:14166-1openSUSE-SU-2024:11280-1

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-2018-1000518 updated cvss 5.9

python-websockets: Improper handling of highly compressed data

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

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

Exploit prediction

1.80% chance of exploitation in the next 30 days, higher than 78% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/aaugustin/websockets/pull/407 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P
GitHub 3.0 7.5 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
pypi websockets
>=4.0, <5.0
<5.0
5.0

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption

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.