⚠️ Security fixes

High severity

• GHSA-4cwx-7wf7-3272: malformed qualified private Cache-Control directives could cause cross-user information disclosure in shared caches or a parse-time crash. The cache parser now treats empty qualified directives conservatively and safely handles mixed qualified and unqualified directives. Fixed by 4fe5bc5f with regression coverage in 9f09b49a.

Medium severity

• GHSA-m8rv-5g2x-5cg5: a malicious type property on a duck-typed blob-like HTTP/1.1 request body could inject CRLF sequences into the generated content-type header. Undici now coerces and validates the value before adding it to the request. Fixed by 7d3cf924.
• GHSA-jr45-8vmc-qm54: optional whitespace around = in qualified no-cache and private directives could bypass shared-cache restrictions and disclose authenticated data across users. Cache-Control parsing now normalizes these forms and applies conservative cache decisions. Fixed by c601fff1.
• GHSA-8xcm-r25x-g524: the retry interceptor could expose a stale Content-Length after resuming a partial response, potentially causing downstream response desynchronization, hangs, or corruption. Undici now rejects partial responses whose Content-Length is inconsistent with Content-Range. Fixed by e11a68ed, with corrected fixtures in 2b3f7493.
• GHSA-v3r7-h72x-cjcm: unsanitized domain and unparsed values passed to setCookie() could inject cookie attributes. Undici now validates cookie domains, paths, and unparsed attributes more strictly. Fixed by 10d93fc3.

Additional hardening

Undici now validates non-string header values after coercion, including array elements, preventing crafted toString() or Symbol.toPrimitive implementations from introducing CRLF sequences. This defense-in-depth change was made in 354a151f.

What's Changed

• fix(decompress): preserve response trailers by @Ram-blip in #5572
• build(deps-dev): bump ws from 8.21.0 to 8.21.1 by @dependabot[bot] in #5576
• fix: validate coerced header values for CRLF by @mcollina in #5579
• fix: handle frozen globalThis in setGlobalDispatcher by @mhayk in #5574
• Ignore auto-generated .npmrc on Windows by @tsctx in #5583

New Contributors

• @mhayk made their first contribution in #5574

Full Changelog: v8.8.0...v8.9.0