Nodejs Undici
CVE-2026-84890
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.
What this means for your business
- It affects Nodejs Undici. It matters if your company, or a supplier that handles your data, runs it.
- An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.
- FIRST's prediction model gives it a 0.3% chance of attack attempts being seen in the next 30 days, ranking above 16% of all known flaws.
What to do
- 1Check whether your company or your suppliers run Nodejs Undici, and which version. The affected versions are listed further down this page.
- 2If you do, apply the vendor's fix. A patch or vendor advisory has been published.
Fastnexa security experts
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Scoring
- CVSS
- 5.9 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H- Weakness
- CWE-770
- Assigned by
- ce714d77-add3-4f53-aff5-83d477b104bb
Dates
- Published
- 2026-09-04
- Last modified
- 2026-09-11
- Sources
- NVD
Affected products
- Nodejs Undici7.15.0 - 7.29.1, 8.0.0 - 8.10.2
As listed in the NVD configuration data. Not a statement about your estate.