CRLF Injection Affecting undici package, versions <6.28.0>=7.0.0 <7.29.0>=8.0.0 <8.9.0
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-JS-UNDICI-18426067
- published30 Jul 2026
- disclosed29 Jul 2026
- creditmcollina
Introduced: 29 Jul 2026
NewCVE-2026-15157 (opens in a new tab)How to fix?
Upgrade undici to version 6.28.0, 7.29.0, 8.9.0 or higher.
Overview
undici is an An HTTP/1.1 client, written from scratch for Node.js
Affected versions of this package are vulnerable to CRLF Injection via the writeH1 path in lib/dispatcher/client-h1.js. An attacker can append arbitrary HTTP headers or smuggle a second request by supplying a duck-typed blob-like body whose .type contains \r\n when an application sends it through request(), stream(), pipeline(), or dispatch() without an explicit content-type header. The vulnerable code copies body.type directly into the outgoing content-type header, so the injected newline sequence is written on the wire and processed by the upstream HTTP/1.1 server. This can corrupt request handling and expose or alter requests sent by the user.