How severe is CVE-2018-1000518?

CVE-2018-1000518 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2018-1000518 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-1000518?

CVE-2018-1000518 affects Websockets Project Websockets. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2018-1000518?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2018-1000518 published?

CVE-2018-1000518 was published on 2018-06-26 and last updated on 2026-06-17.

CVE-2018-1000518

CVE-2018-1000518 is a high-severity vulnerability in Websockets Project Websockets with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-400.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 2% (76th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-400
Affected product: Websockets Project Websockets
Published: 2018-06-26
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2018-1000518?: 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.
How severe is CVE-2018-1000518?: CVE-2018-1000518 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2018-1000518 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-1000518?: CVE-2018-1000518 affects Websockets Project Websockets. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2018-1000518?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2018-1000518 published?: CVE-2018-1000518 was published on 2018-06-26 and last updated on 2026-06-17.

References

https://github.com/aaugustin/websockets/pull/407

Affected products (1)

cpe:2.3:a:websockets_project:websockets:4.0:*:*:*:*:python:*:*

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