Bug 2553726 (CVE-2026-87029) - CVE-2026-87029 undici: undici: Denial of Service via unhandled exception in decompress interceptor
Summary: CVE-2026-87029 undici: undici: Denial of Service via unhandled exception in d...
Keywords:
Status: NEW
Alias: CVE-2026-87029
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-10-15 19:23 UTC by OSIDB Bzimport
Modified: 2026-10-16 15:34 UTC (History)
67 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-10-15 19:23:50 UTC
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.


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