undici vulnerable to Denial of Service via unhandled exception in the decompress interceptor

## Impact undici's `decompress` interceptor forwards decompressed response data to the downstream handler from zlib stream event callbacks without catching exceptions those callbacks may throw. undici's engine converts a synchronous throw from a downstream handler into a per-request failure, but that protection is not in place when the throw happens asynchronously from a zlib callback. As a result, a downstream handler that throws by design, for example the built-in `dump` interceptor which throws when a response exceeds its `maxSize`, escapes as an uncaught exception and terminates the Node.js process. A malicious or compromised HTTP server can crash any client that composes the `decompress` interceptor with `dump` (or another response handler that throws), by returning a small compressed body that decompresses to more than the configured limit. The compressed bytes on the wire are tiny, so only the decompressed size matters. If the application keeps the process alive with a global uncaught-exception handler, the affected request instead hangs until the body timeout. ## Patches Upgrade to undici 7.30.1 or 8.12.2. ## Workarounds Avoid composing the `decompress` interceptor with a response handler that throws during response processing (such as `dump` with a `maxSize`) until upgrading.

Source published

27 Oct 2026 19:02:10 UTC

Source modified

27 Oct 2026 19:15:22 UTC

Observed here

27 Oct 2026 20:46:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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CVSS_V3 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

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