CVE-2020-36406
CVE-2020-36406 is a high-severity vulnerability in Uwebsockets Project Uwebsockets with a CVSS 3.x base score of 8.8. 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-787.
Key facts
- Severity: High (CVSS 3.x base score 8.8)
- CVSS v2: 6.8
- EPSS exploit prediction: 2% (72nd percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-787
- Affected product: Uwebsockets Project Uwebsockets
- Published:
- Last modified:
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
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
- How severe is CVE-2020-36406?
- CVE-2020-36406 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2020-36406 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (72nd percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2020-36406?
- CVE-2020-36406 primarily affects Uwebsockets Project Uwebsockets. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2020-36406?
- 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-2020-36406 published?
- CVE-2020-36406 was published on 2021-07-01 and last updated on 2026-06-17.
References
- https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=25381
- https://github.com/google/oss-fuzz-vulns/blob/main/vulns/uwebsockets/OSV-2020-1695.yaml
- https://github.com/uNetworking/uWebSockets/commit/03fca626a95130ab80f86adada54b29d27242759
Affected products (2)
- cpe:2.3:a:uwebsockets_project:uwebsockets:18.11.0:*:*:*:*:node.js:*:*
- cpe:2.3:a:uwebsockets_project:uwebsockets:18.12.0:*:*:*:*:node.js:*:*
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