CVE-2026-84890 PUBLISHED

undici vulnerable to Denial of Service via unbounded decompression of compressed responses

Assigner: openjs
Reserved: 02.09.2026 Published: 04.09.2026 Updated: 04.09.2026

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.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS Score: 5.9

Product Status

Vendor undici
Product undici
Versions Default: unaffected
  • affected from 7.15.0 to 7.29.1 (excl.)
  • Version 7.29.1 is unaffected
  • affected from 8.0.0 to 8.10.2 (excl.)
  • Version 8.10.2 is unaffected

Credits

  • mcollina analyst
  • UlisesGascon remediation reviewer

References

Problem Types

  • CWE-770: Allocation of Resources Without Limits or Throttling CWE