# CVE-2026-123868: Denial of service in node

> Unauthenticated HTTP/2 clients can exhaust Node.js server memory by sending DATA on undrained streams, affecting Node.js servers using HTTP/2.

- **Severity:** Medium 5.9 (`CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Harmful if only installed:** No
- **Needs a specific call:** No
- **Fix available:** Yes
- **Published:** 11 Nov 2026
- **Updated:** 11 Nov 2026
- **Also known as:** ALPINE-CVE-2026-123868, BELL-CVE-2026-123868, DEBIAN-CVE-2026-123868, GHSA-fxrg-pjjh-rp27, UBUNTU-CVE-2026-123868

## What is CVE-2026-123868?

CVE-2026-123868 is a medium-severity denial of service vulnerability in nodejs node, published on 11 Nov 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An unauthenticated HTTP/2 client can exhaust Node.js server memory because inbound DATA queued on an undrained stream is charged to no session budget. Each inbound DATA frame creates one JavaScript Buffer view in the receiving stream's readable queue, but nothing charges that queue to current_session_memory_: the socket read buffer is accounted only during parsing and released immediately, so whatever stays queued is accounted to nothing. A peer that fills a stream's receive window with one-byte DATA frames pays about 10 wire bytes per frame while the server retains about 114 bytes per frame, so a single stream on one connection can retain hundreds of megabytes from tens of megabytes sent. maxSessionMemory neither bounds the growth nor refuses new streams, because Http2Session::CanAddStream gates admission on the same counter that never sees the queue. This vulnerability affects Node.js 26.x and 24.x.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2026-123868?

An affected version is exposed as installed. No special setting or call is needed.


## How do I fix CVE-2026-123868?

No fix published yet.

## Is CVE-2026-123868 being exploited?

There is no known exploitation of CVE-2026-123868 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-123868 and fix it if it is affected.

What it is: CVE-2026-123868 is a medium-severity denial of service vulnerability in nodejs node, published on 11 Nov 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-123868 in the wild and no public exploit code.
Exposure: An affected version is exposed as installed. No special setting or call is needed.

Affected product: nodejs node. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-123868/ (Markdown: https://insights.sbomify.com/CVE-2026-123868/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-123868
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-123868
- OSV: https://osv.dev/vulnerability/CVE-2026-123868

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-123868/
Summaries are generated and may contain mistakes; the official description above is the record.