CVE-2026-123866
Node.js is vulnerable to HTTP/2 response memory disclosure via a use-after-free during stream teardown
Description
A use-after-free in Node.js HTTP/2 stream teardown can leak response memory, including the contents of other connections' response buffers, to a peer. When a stream is torn down while a write is still backpressured, for example by a peer RST_STREAM or by the server's own per-stream timeout destroying the stream, the stream's response buffer is freed but a reference to it is still used, so freed or unrelated heap memory is written to the socket instead of the intended response. On Node.js 26.x and 24.x the teardown can be driven purely by a remote peer once the window-size change from 26.9.0 and 24.22.0 is present, and on all supported lines the same defect is reachable through an application-initiated teardown such as a per-stream idle timeout. This vulnerability affects Node.js 26.x, 24.x, and 22.x.
INFO
Published Date :
Nov. 11, 2026, 7:17 p.m.
Last Modified :
Nov. 11, 2026, 7:17 p.m.
Remotely Exploit :
No
Source :
ce714d77-add3-4f53-aff5-83d477b104bb
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.0 | HIGH | ce714d77-add3-4f53-aff5-83d477b104bb | ||||
| CVSS 3.0 | HIGH | MITRE-CVE |
Solution
- Update Node.js to a version that fixes the issue.
- Apply patches for Node.js 26.x, 24.x, and 22.x.
- Review stream teardown and timeout configurations.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-123866.
| URL | Resource |
|---|---|
| https://cna.openjsf.org/security-advisories.html | |
| https://nodejs.org/en/blog/vulnerability/november-2026-security-releases |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-123866 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-123866
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-123866 vulnerability anywhere in the article.
-
The Hacker News
Node.js Fixes 16 Flaws, Including HTTP/2 Bugs That Crash Servers and Leak Other Connections' Data
A flaw fixed in Node.js this week lets unauthenticated clients crash servers that use the runtime's built-in HTTP/2 support on the 24.x and 26.x release lines. A second HTTP/2 flaw can cause a server ... Read more
The following table lists the changes that have been made to the
CVE-2026-123866 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by ce714d77-add3-4f53-aff5-83d477b104bb
Nov. 11, 2026
Action Type Old Value New Value Added Description A use-after-free in Node.js HTTP/2 stream teardown can leak response memory, including the contents of other connections' response buffers, to a peer. When a stream is torn down while a write is still backpressured, for example by a peer RST_STREAM or by the server's own per-stream timeout destroying the stream, the stream's response buffer is freed but a reference to it is still used, so freed or unrelated heap memory is written to the socket instead of the intended response. On Node.js 26.x and 24.x the teardown can be driven purely by a remote peer once the window-size change from 26.9.0 and 24.22.0 is present, and on all supported lines the same defect is reachable through an application-initiated teardown such as a per-stream idle timeout. This vulnerability affects Node.js 26.x, 24.x, and 22.x. Added CVSS V3 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Added CWE CWE-416 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/123xxx/CVE-2026-123866.json">CVE-2026-123866</a> Added Reference https://cna.openjsf.org/security-advisories.html Added Reference https://nodejs.org/en/blog/vulnerability/november-2026-security-releases