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.
- 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
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
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.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-123868 being exploited?
There is no known exploitation of CVE-2026-123868 in the wild and no public exploit code.
Sources
Also known as ALPINE-CVE-2026-123868, BELL-CVE-2026-123868, DEBIAN-CVE-2026-123868, GHSA-fxrg-pjjh-rp27, UBUNTU-CVE-2026-123868.