CVE-2026-97200 Unbounded response body buffering and decompression in hackney
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-97200?
CVE-2026-97200 is a high-severity vulnerability in benoitc hackney, published on 26 Oct 2026.
Official description
Allocation of Resources Without Limits or Throttling vulnerability in hackney_conn in benoitc hackney allows a malicious HTTP server to exhaust client memory via an oversized or highly compressed response body. hackney:request/5 and hackney:body/1 return the whole response body, and nothing bounds how much the connection process buffers. Any server the client requests can trigger it.
hackney_conn:read_full_body/2 and the HTTP/2 and HTTP/3 accumulators append every chunk until the body ends. With {auto_decompress, true} the buffered body is then inflated in one step with zlib:gunzip/1 or zlib:inflate/2, which return the whole output at once.
This issue affects hackney: from 2.0.0-beta.1 before 4.9.0.
Which versions are affected by CVE-2026-97200?
1 open source package ship an affected version, including hackney.
| Package | Affected | Fixed in |
|---|---|---|
hackney Hex | From 2.0.0-beta.1 | 4.9.0 |
How do I fix CVE-2026-97200?
Upgrade hackney to 4.9.0 or later.
Is CVE-2026-97200 being exploited?
There is no known exploitation of CVE-2026-97200 in the wild and no public exploit code.
Sources
Also known as EEF-CVE-2026-97200, GHSA-wpmp-4grc-56ph.