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

CVE-2026-84890 is fixed in 12 products on 1 platform, first by DEBIAN-CVE-2026-84890, released September 10, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-84890
- Priority: Routine
- CVSS: 5.9 (medium)
- EPSS: 0.0041
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 4, 2026

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | node-undici Debian 14 | 8.10.2+dfsg+~cs3.2.2-1 | [DEBIAN-CVE-2026-84890](https://patchblox.com/security/data/fix/linux/debian-cve-2026-84890.md) | Sep 10, 2026 |
| Linux | nodejs24 amzn 2023 | 1:24.21.0-1.amzn2023.0.1 | [ALAS2023-2026-3107](https://patchblox.com/security/data/fix/linux/alas2023-2026-3107.md) | Sep 28, 2026 |
| Linux | nodejs24-debuginfo amzn 2023 | 1:24.21.0-1.amzn2023.0.1 | [ALAS2023-2026-3107](https://patchblox.com/security/data/fix/linux/alas2023-2026-3107.md) | Sep 28, 2026 |
| Linux | nodejs24-debugsource amzn 2023 | 1:24.21.0-1.amzn2023.0.1 | [ALAS2023-2026-3107](https://patchblox.com/security/data/fix/linux/alas2023-2026-3107.md) | Sep 28, 2026 |
| Linux | nodejs24-devel amzn 2023 | 1:24.21.0-1.amzn2023.0.1 | [ALAS2023-2026-3107](https://patchblox.com/security/data/fix/linux/alas2023-2026-3107.md) | Sep 28, 2026 |
| Linux | nodejs24-docs amzn 2023 | 1:24.21.0-1.amzn2023.0.1 | [ALAS2023-2026-3107](https://patchblox.com/security/data/fix/linux/alas2023-2026-3107.md) | Sep 28, 2026 |
| Linux | nodejs24-full-i18n amzn 2023 | 1:24.21.0-1.amzn2023.0.1 | [ALAS2023-2026-3107](https://patchblox.com/security/data/fix/linux/alas2023-2026-3107.md) | Sep 28, 2026 |
| Linux | nodejs24-libs amzn 2023 | 1:24.21.0-1.amzn2023.0.1 | [ALAS2023-2026-3107](https://patchblox.com/security/data/fix/linux/alas2023-2026-3107.md) | Sep 28, 2026 |
| Linux | nodejs24-libs-debuginfo amzn 2023 | 1:24.21.0-1.amzn2023.0.1 | [ALAS2023-2026-3107](https://patchblox.com/security/data/fix/linux/alas2023-2026-3107.md) | Sep 28, 2026 |
| Linux | nodejs24-npm amzn 2023 | 1:11.19.0-1.24.21.0.1.amzn2023.0.1 | [ALAS2023-2026-3107](https://patchblox.com/security/data/fix/linux/alas2023-2026-3107.md) | Sep 28, 2026 |
| Linux | pi-coding-agent opensuse-leap 16.0 | 1.0.4-bp160.1.1 | [OPENSUSE-SU-2026:22111-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22111-1.md) | Nov 7, 2026 |
| Linux | v8-13.6-devel amzn 2023 | 3:13.6.233.17-1.24.21.0.1.amzn2023.0.1 | [ALAS2023-2026-3107](https://patchblox.com/security/data/fix/linux/alas2023-2026-3107.md) | Sep 28, 2026 |

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Data as of 2026-11-09T07:25:28Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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