CVE-2021-22940Network attack vector

Process behavior change via HTTP/2 stream cancellation

Published Aug 16, 2021 · Updated Apr 30, 2025

Use-after-free in Node.js HTTP/2 stream cancellation before 16.6.1 allows remote attackers to change process behavior via crafted stream cancellation. The close path for canceled HTTP/2 streams can access memory after it has been released, causing corruption. Exploitation requires a network peer able to send HTTP/2 stream-cancellation traffic; the resulting impact is process-behavior change rather than guaranteed code execution.

CVSS severity7.5
High
EPSS probability13.86%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Node.js HTTP/2 stream cancellation before 16.6.1 allows remote attackers to change process behavior via crafted stream cancellation. The close path for canceled HTTP/2 streams can access memory after it has been released, causing corruption. Exploitation requires a network peer able to send HTTP/2 stream-cancellation traffic; the resulting impact is process-behavior change rather than guaranteed code execution.

The record

CVE
CVE-2021-22940
Published
Aug 16, 2021
Updated
Apr 30, 2025
Vendor
Node.js
Product
Node.js
Classifications
CWE-416, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 16, 2021CVE publishedPublication date reported by the CVE source.
  2. Apr 30, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.0 <10.*
  2. Affected versionversion=11.0 <11.*
  3. Affected versionversion=12.0 <12.22.5
  4. Affected versionversion=13.0 <13.*
  5. Affected versionversion=14.0 <14.17.5
  6. Affected versionversion=15.0 <15.*
  7. Affected versionversion=16.0 <16.6.2
  8. Affected versionversion=4.0 <4.*
  9. Affected versionversion=5.0 <5.*
  10. Affected versionversion=6.0 <6.*
  11. Affected versionversion=7.0 <7.*
  12. Affected versionversion=8.0 <8.*
  13. Affected versionversion=9.0 <9.*

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Node.js · Node.jsversion=10.0 <10.*; version=11.0 <11.*; version=12.0 <12.22.5; version=13.0 <13.*; version=14.0 <14.17.5; version=15.0 <15.*; version=16.0 <16.6.2; version=4.0 <4.*; version=5.0 <5.*; version=6.0 <6.*; version=7.0 <7.*; version=8.0 <8.*; version=9.0 <9.*

Published CVSS scores

5.0NVDAV:N/AC:L/Au:N/C:N/I:P/A:N
7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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