CVE-2020-36406

Name: CVE-2020-36406
Creator: NVD / NIST
Published: 2021-07-01T03:15:08+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.8/10EPSS 1.52%

Last modified Jun 17, 2026

CVE-2020-36406 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. 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. EPSS estimates a 1.52% chance of exploitation in the next 30 days.

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

Metrics

CVSS 3.1

8.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS Probability

1.52%

71.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-787

Affected Software

Vendor	Product	Versions
Uwebsockets Project	Uwebsockets	18.11.0
Uwebsockets Project	Uwebsockets	18.12.0

References

https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=25381Exploit, Issue Tracking, Patch, Third Party Advisory
https://github.com/google/oss-fuzz-vulns/blob/main/vulns/uwebsockets/OSV-2020-1695.yamlThird Party Advisory
https://github.com/uNetworking/uWebSockets/commit/03fca626a95130ab80f86adada54b29d27242759Patch, Third Party Advisory
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=25381Exploit, Issue Tracking, Patch, Third Party Advisory
https://github.com/google/oss-fuzz-vulns/blob/main/vulns/uwebsockets/OSV-2020-1695.yamlThird Party Advisory
https://github.com/uNetworking/uWebSockets/commit/03fca626a95130ab80f86adada54b29d27242759Patch, Third Party Advisory

Timeline

Published: Jul 1, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-36406?

How severe is CVE-2020-36406?

CVE-2020-36406 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 1.52% probability of exploitation in the next 30 days.

How do I fix CVE-2020-36406?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-36406?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST