CVE-2026-21714: A memory leak occurs in Node.js HTTP/2 servers when a client sends WINDOW_UPDATE frames on stream 0 (connectio

Routine

MEDIUM 5.3REMOTEUPGRADE

CVE-2026-21714 is a medium-severity flaw (CVSS 5.3) affecting node.js. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A memory leak occurs in Node.js HTTP/2 servers when a client sends WINDOW_UPDATE frames on stream 0 (connection-level) that cause the flow control window to exceed the maximum value of 2³¹-1. The server correctly sends a GOAWAY frame, but the Http2Session object is never cleaned up. This vulnerability affects HTTP2 users on Node.js 20, 22, 24 and 25.

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 63%)
CISA exploited list	No
Weakness	CWE-401
Published	2026-03-30
Last modified	2026-08-19

Publisher (CNA): HackerOne · Vendor: nodejs

Last updated 2026-08-19 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-03-30 20:16 UTCPublished CVE record published
2026-08-19 13:35 UTCUpdated Record last modified

nodejs node.js UPGRADE

Affected: <= 20.20.1 · >= 22.0.0 and <= 22.22.1 · >= 24.0.0 and <= 24.14.0 · >= 25.0.0 and <= 25.8.1

Fixed in: newer than 25.8.1

Safe to downgrade to: a release before 22.0.0

1. Check installed version

apt-cache policy node.js || rpm -q node.js || node.js --version

2. UPGRADE to newer than 25.8.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade node.js

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade node.js

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 22.0.0 (Debian / Ubuntu)

apt-cache madison node.js sudo apt install node.js=<VERSION_BEFORE_22.0.0> sudo apt-mark hold node.js

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list node.js sudo dnf downgrade node.js-<VERSION_BEFORE_22.0.0> sudo dnf versionlock add node.js

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-21714?

node.js: upgrade to newer than 25.8.1. Exact commands for each OS are on this page.

Is CVE-2026-21714 being exploited?

CVE-2026-21714 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-21714 affect?

CVE-2026-21714 affects node.js. Severity is medium (CVSS 5.3). A memory leak occurs in Node.js HTTP/2 servers when a client sends WINDOW_UPDATE frames on stream 0 (connection-level) that cause the flow control window to exceed the maximum value of 2³¹-1. The server correctly sends a GOAWAY frame, but t

How urgent is CVE-2026-21714?

Priority 33/100. Remotely exploitable, no login, no user action

Software pages

Node.js vulnerabilities

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References

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