CVE-2021-22883Network attack vector

Service interruption via unreleased HTTP/2 connections

Published Mar 3, 2021 · Updated Apr 30, 2025

Resource-exhaustion DoS in the HTTP/2 server of Node.js allows remote attackers to interrupt service through repeated protocol negotiation. The unknownProtocol handling path leaves connection sockets and their file descriptors unreleased after failed negotiations. The target must expose the affected HTTP/2 server path; repeated attempts can block new connections or consume memory until the host runs out.

CVSS severity7.5
High
EPSS probability74.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource-exhaustion DoS in the HTTP/2 server of Node.js allows remote attackers to interrupt service through repeated protocol negotiation. The unknownProtocol handling path leaves connection sockets and their file descriptors unreleased after failed negotiations. The target must expose the affected HTTP/2 server path; repeated attempts can block new connections or consume memory until the host runs out.

The record

CVE
CVE-2021-22883
Published
Mar 3, 2021
Updated
Apr 30, 2025
Vendor
Node.js
Product
Node.js
Classifications
CWE-400, CWE-772, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 3, 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 <10.24.0
  2. Affected versionversion=11.0 <11.*
  3. Affected versionversion=12.0 <12.21.0
  4. Affected versionversion=13.0 <13.*
  5. Affected versionversion=14.0 <14.16.0
  6. Affected versionversion=15.0 <15.10.0
  7. Affected versionversion=4.0 <4.*
  8. Affected versionversion=5.0 <5.*
  9. Affected versionversion=6.0 <6.*
  10. Affected versionversion=7.0 <7.*
  11. Affected versionversion=8.0 <8.*
  12. Affected versionversion=9.0 <9.*

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Node.js · Node.jsversion=10.0 <10.24.0; version=11.0 <11.*; version=12.0 <12.21.0; version=13.0 <13.*; version=14.0 <14.16.0; version=15.0 <15.10.0; 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

7.8NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:C
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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-400Uncontrolled Resource Consumption
CWE-772Missing Release of Resource after Effective Lifetime
T1499.004Application or System Exploitation

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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