VulnerabilityPublished 6 Apr 2026Updated 8 Sep 2026

CVE-2026-21714: Node.js HTTP/2 servers · Memory Leak Occurs

Affects nodeSource GCVE Database

Authoritative record:CVE-2026-21714· Medium 5.3

Not known to be exploited · CVSS 5.3 Medium · fixed in 25.8.2 : update node when convenient.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.0 base score

5.3Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.4% chance of exploitation in 30 days – higher than 39% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 25.8.2, 24.14.1, 22.22.2 +1

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: Low

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 30 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade node to 25.8.2, 24.14.1, 22.22.2 or 20.20.2.

Affected software

Product	Affected	Fixed in
Bitnaminode`pkg:bitnami/node`Other threats	Affected <20.20.2 >=21.0.0 <22.22.2 >=23.0.0 <24.14.1 >=25.0.0 <25.8.2	Fixed in 20.20.2 22.22.2 24.14.1 25.8.2

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available for this vulnerability. Users should upgrade to Node.js versions 20.20.2 or later, 22.22.2 or later, 24.14.1 or later, and 25.8.2 or later to remediate this issue. No additional mitigation steps are indicated beyond applying the official fixes.

Description

A memory leak vulnerability exists in Node.js HTTP/2 servers when a client sends WINDOW_UPDATE frames on stream 0 that cause the flow control window to exceed the maximum allowed value. Although the server responds with a GOAWAY frame, the associated Http2Session object is not properly cleaned up, leading to resource leakage. This affects multiple Node.js versions including 20, 21, 23, and 25 within specified version ranges.

Impact

The vulnerability causes a memory leak on affected Node.js HTTP/2 servers, which could degrade server performance or lead to resource exhaustion over time. The server does send a GOAWAY frame to close the connection properly, but the lingering Http2Session object consumes memory unnecessarily. There is no indication of direct code execution or data compromise from this vulnerability.

Summary

CVE-2026-21714 describes a memory leak in Node.js HTTP/2 servers triggered by client-sent WINDOW_UPDATE frames on stream 0 (connection-level) that cause the flow control window to exceed 2³¹-1. The server correctly sends a GOAWAY frame to terminate the connection, but the Http2Session object remains allocated and is not cleaned up, resulting in a memory leak. This issue affects Node.js versions prior to 20.20.2, versions from 21.0.0 up to but not including 22.22.2, versions from 23.0.0 up to but not including 24.14.1, and versions from 25.0.0 up to but not including 25.8.2.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 8 Sep 2026, 13:36 UTC

Technical details

References

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