VulnerabilityPublished 11 Nov 2026

CVE-2026-123866: nodejs node · Use After Free

Affects nodejs nodeSource CVE Database V5

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Not known to be exploited · CVSS 7.5 High · fixed in 26.13.1 : patch nodejs node soon.

Data as of 11 Nov 2026, 18:35 UTC

CVSS 3.0 base score

7.5High

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

Thin evidence

One scorer or none

CVSS scores by source
CNA (openjs)	CVSS 3.0	7.5

Patch: Available – fixed in 26.13.1, 24.22.3, 22.23.5

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

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

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: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 11 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 11 Nov 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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 nodejs node to 26.13.1, 24.22.3 or 22.23.5.

Affected software

Product	Affected	Fixed in
nodejsnode	Affected >=25.0.0 <26.13.1	Fixed in 26.13.1
nodejsnode	Affected >=23.0.0 <24.22.3	Fixed in 24.22.3
nodejsnode	Affected <22.23.5	Fixed in 22.23.5

AI-suggested

Fixed versions are available: Node.js 22.23.5, 24.22.3, and 26.13.1. Users should upgrade to these or later versions to remediate the vulnerability. No additional mitigation steps are indicated.

Description

CVE-2026-123866 is a use-after-free vulnerability in Node.js HTTP/2 stream teardown that can cause response memory leakage. This flaw allows memory from other connections' response buffers to be sent to a peer when a stream is torn down during backpressure on writes. It affects Node.js versions 22.x, 24.x, and 26.x prior to specific fixed releases.

Impact

An attacker can cause memory from other connections' response buffers to be leaked to a peer, potentially exposing sensitive data. The vulnerability does not affect integrity or availability but has a high confidentiality impact. There are no known exploits in the wild as of the published date.

Summary

This vulnerability involves a use-after-free condition in the HTTP/2 stream teardown process in Node.js. When a stream is destroyed while a write operation is backpressured, the response buffer is freed but still referenced, causing freed or unrelated heap memory to be sent to the socket instead of the intended response data. The issue can be triggered remotely via peer RST_STREAM frames or server-initiated stream timeouts. It affects Node.js versions 22.x, 24.x, and 26.x before the fixed versions 22.23.5, 24.22.3, and 26.13.1 respectively.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 11 Nov 2026, 18:35 UTC

Technical details

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