# CVE-2026-123868: Node.js HTTP/2 memory exhaustion denial of service via unaccounted inbound DATA

Source: https://junglewise.ai/threats/cve-2026-123868-an-unauthenticated-http-2-client-can-exhaust-node-js-server  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-11. Updated: 2026-11-11  
License: CC BY 4.0 with a link back

CVE-2026-123868 · Severity: medium · CVSS 5.9 · Published 2026-11-11

Node.js is a server runtime used to build network applications. An unauthenticated HTTP/2 client can exhaust server memory by sending specially crafted data frames, causing the server to crash or become unresponsive. A single attacker can consume hundreds of megabytes of memory on the target server using only tens of megabytes of network traffic.

Technologies: [OpenJS Foundation Node.js](https://junglewise.ai/threats/technologies/openjs-foundation-node-js). Vendors: [OpenJS Foundation](https://junglewise.ai/threats/vendors/openjs-foundation).

## Quick answers

**Is CVE-2026-123868 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-123868 being exploited in the wild.

**How severe is CVE-2026-123868?** Medium severity, with a CVSS score of 5.9, published 11 November 2026.

**Which products and versions are affected?** OpenJS Foundation Node.js 26.x, 24.x.

**Is there a fix for CVE-2026-123868?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-123868 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-123868?** Check whether you run OpenJS Foundation Node.js at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability exploits HTTP/2 stream receive buffers that are not charged against the session memory budget. An attacker sends small one-byte DATA frames that fill a stream's receive window; each frame creates a JavaScript Buffer view in the receiving queue, but the session memory counter never accounts for it. This allows an attacker to retain ~114 bytes per frame on the server while sending only ~10 wire bytes per frame, enabling rapid memory exhaustion on a single stream within one connection.

## Affected products

- OpenJS Foundation Node.js 26.x, 24.x

## Timeline

- 2026-11-11: disclosed

## References

- [https://cna.openjsf.org/security-advisories.html](https://cna.openjsf.org/security-advisories.html)
- [https://nodejs.org/en/blog/vulnerability/november-2026-security-releases](https://nodejs.org/en/blog/vulnerability/november-2026-security-releases)

## Related threats

- [Node.js TLS server use-after-destroy in deferred handshake callbacks](https://junglewise.ai/threats/cve-2026-126051-a-deferred-callback-use-after-destroy-in-node-js-tls-server)
- [Node.js https.Agent certificate validation bypass via TLS session reuse](https://junglewise.ai/threats/cve-2026-123877-a-certificate-validation-bypass-in-node-js-https-agent-lets-a)
- [Node.js HTTP/2 denial of service via NULL pointer dereference](https://junglewise.ai/threats/cve-2026-123875-a-null-pointer-dereference-in-node-js-http-2-lets-an)
- [Node.js HTTP/2 use-after-free in respondWithFile stream reset](https://junglewise.ai/threats/cve-2026-123874-a-use-after-free-in-node-js-http-2-lets-an-unauthenticated)
- [Node.js client certificate auth bypass via TLS 1.2 renegotiation servername change](https://junglewise.ai/threats/cve-2026-123872-a-client-certificate-authentication-bypass-in-node-js-tls-lets-a)