Описание
undici vulnerable to CRLF Injection via blob-like body 'type' property
Impact
When an application passes a duck-typed blob-like body to undici's HTTP/1.1 dispatcher (via request(), stream(), pipeline(), or dispatch()) with a .type derived from untrusted input, an attacker can inject CRLF sequences (\r\n) to append arbitrary HTTP headers and potentially smuggle a second request past the upstream.
The vulnerable branch in lib/dispatcher/client-h1.js pushes body.type directly into the outgoing headers with no validation, while every other header path in undici goes through isValidHeaderValue():
The bug requires a hand-rolled duck-typed blob object or a Blob subclass with a controlled .type. Native Blob is safe because its constructor strips CRLF from .type. fetch() is unaffected because it validates via the Headers class. Ecosystem consumers that build duck-typed blob shapes from user input include form-data-encoder, formdata-polyfill, and formdata-node.
Same defect class as CVE-2022-35948 (explicit content-type sink, fixed in undici 5.8.2) and CVE-2026-1527 (upgrade option sink, fixed in 6.24.0 / 7.24.0), both closed by adding isValidHeaderValue() on their respective sinks. This branch was missed.
Patches
Patched in undici v6.28.0, v7.29.0, and v8.9.0. Users should upgrade to one of these versions or later.
Workarounds
- Set an explicit, validated
content-typeheader on the request options (skips the vulnerable branch). - Use a native
Blob(orfetch-blob) instead of a hand-rolled duck-typed object. - Reject control characters in the MIME type before assigning it to
.type. - Use
fetch()instead of the non-fetchAPIs.
Ссылки
- https://github.com/nodejs/undici/security/advisories/GHSA-m8rv-5g2x-5cg5
- https://nvd.nist.gov/vuln/detail/CVE-2026-15157
- https://github.com/nodejs/undici/commit/33928bc24f742ea8422ed90d17f2e0cc83e4d09d
- https://github.com/nodejs/undici/commit/740a0b7c173cb4a83a5b693e96e8f3a116cfc400
- https://github.com/nodejs/undici/commit/7d3cf924c262c486bc77f951348f4e5c847b7b42
- https://cna.openjsf.org/security-advisories.html
- https://github.com/nodejs/undici/releases/tag/v6.28.0
- https://github.com/nodejs/undici/releases/tag/v7.29.0
- https://github.com/nodejs/undici/releases/tag/v8.9.0
Пакеты
undici
< 6.28.0
6.28.0
undici
>= 7.0.0, < 7.29.0
7.29.0
undici
>= 8.0.0, < 8.9.0
8.9.0
Связанные уязвимости
undici does not validate the type property of a duck-typed blob-like request body before using it as the Content-Type header on the HTTP/1.1 dispatcher. In undici before 6.28.0, from 7.0.0 up to before 7.29.0, and from 8.0.0 up to before 8.9.0, an application that passes a hand-rolled blob-like body (via request, stream, pipeline, or dispatch) whose type is derived from untrusted input allows an attacker to inject CRLF sequences and append arbitrary HTTP headers, potentially smuggling a second request past the upstream. Native Blob objects are safe because their constructor strips CRLF from the type, and fetch is unaffected because it validates headers, but ecosystem libraries that build duck-typed blob shapes from user input can reach the vulnerable path. This is the same defect class as CVE-2022-35948 and CVE-2026-1527, on a header sink that the earlier fixes did not cover. The issue is fixed in undici 6.28.0, 7.29.0, and 8.9.0.
undici does not validate the type property of a duck-typed blob-like request body before using it as the Content-Type header on the HTTP/1.1 dispatcher. In undici before 6.28.0, from 7.0.0 up to before 7.29.0, and from 8.0.0 up to before 8.9.0, an application that passes a hand-rolled blob-like body (via request, stream, pipeline, or dispatch) whose type is derived from untrusted input allows an attacker to inject CRLF sequences and append arbitrary HTTP headers, potentially smuggling a second request past the upstream. Native Blob objects are safe because their constructor strips CRLF from the type, and fetch is unaffected because it validates headers, but ecosystem libraries that build duck-typed blob shapes from user input can reach the vulnerable path. This is the same defect class as CVE-2022-35948 and CVE-2026-1527, on a header sink that the earlier fixes did not cover. The issue is fixed in undici 6.28.0, 7.29.0, and 8.9.0.
undici does not validate the type property of a duck-typed blob-like request body before using it as the Content-Type header on the HTTP/1.1 dispatcher. In undici before 6.28.0, from 7.0.0 up to before 7.29.0, and from 8.0.0 up to before 8.9.0, an application that passes a hand-rolled blob-like body (via request, stream, pipeline, or dispatch) whose type is derived from untrusted input allows an attacker to inject CRLF sequences and append arbitrary HTTP headers, potentially smuggling a second request past the upstream. Native Blob objects are safe because their constructor strips CRLF from the type, and fetch is unaffected because it validates headers, but ecosystem libraries that build duck-typed blob shapes from user input can reach the vulnerable path. This is the same defect class as CVE-2022-35948 and CVE-2026-1527, on a header sink that the earlier fixes did not cover. The issue is fixed in undici 6.28.0, 7.29.0, and 8.9.0.
undici does not validate the type property of a duck-typed blob-like r ...