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5.9 Medium

CVE-2026-84890 undici's decompress interceptor decompresses response bodies according to the untrusted Content-Encoding header

Description

undici's decompress interceptor decompresses response bodies according to the untrusted Content-Encoding header. While the number of content-encoding layers is capped, the total decompressed output size is unbounded and there is no configuration option to limit it. A malicious or faulty upstream can therefore return a small compressed payload, a compression bomb, that expands to hundreds of megabytes or more in client memory, an asymmetric resource consumption that can exhaust memory and crash the process. This affects undici versions from 7.15.0 up to 7.29.1 and from 8.0.0 up to 8.10.2. Users should upgrade to undici 7.29.1 or 8.10.2.

Affected products and versions

Product Affected versions Fixed in
undici 8.10 earliest → < 8.10.2 8.10.2
undici 8.0 8.0.0 → < 8.10.2 8.10.2
undici 7.29 earliest → < 7.29.1 7.29.1
undici 7.15 7.15.0 → < 7.29.1 7.29.1

Other CVEs of undici

The 45 CVEs of undici →
CVE-2026-116630 undici vulnerable to cross-user information disclosure via cross-origin redirect revalidation 5.9 Medium CVE-2026-120415 undici vulnerable to cross-origin credential disclosure via array-of-tuples headers bypassing redirect stripping 5.9 Medium CVE-2026-120423 undici vulnerable to Subresource Integrity bypass via whitespace in integrity metadata 5.9 Medium CVE-2026-116592 undici vulnerable to cache poisoning and cross-user disclosure via intermediate redirect hops 7.4 High
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