CVE-2026-87029
MEDIUMDescription
undici is an HTTP client library for Node.js. In versions 7.15.0 through 7.30.0 and 8.0.0 through 8.12.1, its decompress interceptor forwards decompressed response data to the downstream handler from zlib stream event callbacks without catching exceptions those callbacks may throw, and while undici's engine converts a synchronous throw from a downstream handler into a per-request failure, that protection is absent when the throw happens asynchronously from a zlib callback. As a result, a downstream handler that throws by design, such as the built-in dump interceptor which throws when a response exceeds its configured maximum size, escapes as an uncaught exception that terminates the Node.js process. A malicious or compromised HTTP server can crash any client that composes the decompress interceptor with such a handler by returning a small compressed body that decompresses to more than the configured limit, so only the decompressed size matters and the bytes on the wire stay tiny. The issue is fixed in undici 7.30.1 and 8.12.2, and users should upgrade to one of those versions or later. As a workaround, avoid composing the decompress interceptor with a response handler that throws during response processing until upgrading.
Is your site exposed to CVE-2026-87029?
Run a free security scan — no signup, results in seconds.
CVSS v3.1 Score
EPSS — Exploit Prediction
EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.
Weakness Type (CWE)
Affected Products
| Vendor | Product |
|---|---|
| nodejs | undici |
| nodejs | undici |
References
Frequently Asked Questions
What is CVE-2026-87029? +
How severe is CVE-2026-87029? +
What products are affected by CVE-2026-87029? +
How do I check if I'm vulnerable to CVE-2026-87029? +
Related Vulnerabilities
go-ethereum (geth) is a golang execution layer implementation of the Ethereum protocol. A vulnerable node can be forced to shutdown/crash …
tRPC allows users to build & consume fully typesafe APIs without schemas or code generation. In versions starting from 11.0.0 …
Multer is a node.js middleware for handling `multipart/form-data`. A vulnerability that is present starting in version 1.4.4-lts.1 and prior to …
The MCP Python SDK, called `mcp` on PyPI, is a Python implementation of the Model Context Protocol (MCP). Prior to …
The MCP Python SDK, called `mcp` on PyPI, is a Python implementation of the Model Context Protocol (MCP). Prior to …
@builder.io/qwik-city is the meta-framework for Qwik. When a Qwik Server Action QRL is executed it dynamically load the file containing …
