GitHub Advisoryadvisory · npm
GHSA-3xpg-4rpp-hhhm undici vulnerable to Denial of Service via unbounded decompression of compressed responses
MEDIUM
Official page ↗
- Aliases
- CVE-2026-84890
- Ecosystem
- npm
- Packages
- undici
- Severity
- Moderate
- CVSS vector
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weaknesses
- CWE-770
- Reviewed
- 2026-09-29
Affected packages
• npm undici: >= 7.15.0, < 7.29.1 → fixed in 7.29.1
• npm undici: >= 8.0.0, < 8.10.2 → fixed in 8.10.2
Description
Impact
The `interceptors.decompress()` interceptor decompresses HTTP response bodies according to the untrusted `Content-Encoding` header. The number of decompression layers is capped at 5, but the total decompressed output size is not bounded and there is no option to limit it. A malicious or faulty upstream can return a small compressed payload (a compression bomb) that expands to hundreds of megabytes or gigabytes in client memory, exhausting memory and causing the Node.js process to crash or become unresponsive. Any application using the decompress interceptor to read responses from untrusted or compromised upstreams is affected.
Patches
Upgrade to `7.29.1` or `8.10.2`. The interceptor now accepts a `maxSize` option (default 64 MiB) and rejects responses whose decompressed output exceeds it with a `ResponseExceededMaxSizeError`.
Workarounds
Once upgraded, set a conservative `maxSize` on the interceptor. Before upgrading, avoid using `interceptors.decompress()` with untrusted upstreams, or apply a custom interceptor that enforces a decompressed output size limit.
Related
Alias · CVE (1)
- CVE-2026-84890 undici's decompress interceptor decompresses response bodies according to the untrusted Content-Encoding header. vulnerability
Weakness · CWE (1)
- CWE-770 Allocation of Resources Without Limits or Throttling weakness
References
- https://github.com/nodejs/undici/security/advisories/GHSA-3xpg-4rpp-hhhm web
- https://nvd.nist.gov/vuln/detail/CVE-2026-84890 advisory
- https://github.com/nodejs/undici/commit/2c7d7e1227043c644c4c32cfd1e276f4fd4fcb11 web
- https://github.com/nodejs/undici/commit/7aac7f12f757844763c8b8f1ab6e305e80d55838 web
- https://cna.openjsf.org/security-advisories.html web
- https://github.com/nodejs/undici package
- https://github.com/nodejs/undici/releases/tag/v7.29.1 web
- https://github.com/nodejs/undici/releases/tag/v8.10.2 web