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No exploitation reportedFix available

CVE-2020-36406

No exploitation reported by the sources we read.

  • Published2021-07-01
  • WeaknessCWE-787

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

uWebSockets 18.11.0 and 18.12.0 has a stack-based buffer overflow in uWS::TopicTree::trimTree (called from uWS::TopicTree::unsubscribeAll). NOTE: the vendor's position is that this is "a minor issue or not even an issue at all" because the developer of an application (that uses uWebSockets) should not be allowing the large number of triggered topics to accumulate

Timeline

dates in UTC
  1. 2021-07-0103:15CVE publishedNVD

Versions per branch

NVD
Uwebsockets project uwebsocketsversion to verify
BranchAffectedFixed in
18.11= 18.11.0no fix published
18.12= 18.12.0no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Published
2021-07-01
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-8hff-gxvr-v39f

Frequently asked questions

What is CVE-2020-36406?

uWebSockets 18.11.0 and 18.12.0 has a stack-based buffer overflow in uWS::TopicTree::trimTree (called from uWS::TopicTree::unsubscribeAll). NOTE: the vendor's position is that this is "a minor issue or not even an issue at all" because the developer of an application (that uses uWebSockets) should not be allowing the large number of triggered topics to accumulate

Is CVE-2020-36406 actively exploited?

Active exploitation of CVE-2020-36406 has not been confirmed. Its EPSS score was 1.5% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-36406?

CVE-2020-36406 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

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