CVE-2026-123874 Node.js is vulnerable to an HTTP/2 use-after-free via respondWithFile() stream reset during a pending write
Unauthenticated HTTP/2 clients can trigger a use-after-free in Node.js servers serving files with stream.respondWithFile, corrupting memory.
- 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
- Yes
- Fix
- Available
What is CVE-2026-123874?
CVE-2026-123874 is a high-severity use after free 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
A use-after-free in Node.js HTTP/2 lets an unauthenticated client corrupt server memory, over both TLS and cleartext, when the server serves files with respondWithFile() or respondWithFD(). A client can make the server free an Http2Stream while a write request that points to it is still queued on the socket; when that write completes, the code dereferences and makes a virtual call through the freed object. The only precondition is that the application serves a file with stream.respondWithFile() or stream.respondWithFD(), with default settings otherwise. This vulnerability affects Node.js 26.x (since 26.9.0) and 24.x (since 24.22.0).
Weakness: CWE-416
Which versions are affected by CVE-2026-123874?
An affected version is only exploitable if your software calls respondWithFile() or respondWithFD(). Many projects that include it are not exposed.
How do I fix CVE-2026-123874?
Upgrade to a fixed version.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-123874 being exploited?
There is no known exploitation of CVE-2026-123874 in the wild and no public exploit code.
Sources
Also known as ALPINE-CVE-2026-123874, BELL-CVE-2026-123874, DEBIAN-CVE-2026-123874, GHSA-vgqh-cxw6-x64x, UBUNTU-CVE-2026-123874.