# CVE-2026-97200: benoitc hackney denial of service via unbounded buffering

Source: https://junglewise.ai/threats/cve-2026-97200-allocation-of-resources-without-limits-or-throttling  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-26. Updated: 2026-10-26  
License: CC BY 4.0 with a link back

CVE-2026-97200 · Severity: info · Published 2026-10-26

hackney is an Erlang HTTP client library used in applications to make web requests. A malicious HTTP server can cause a client application to exhaust memory by sending a very large or highly compressed response body, since the library buffers entire responses without limits. This allows an attacker to crash any application using hackney to fetch data from an attacker-controlled server.

Technologies: [Benoitc Hackney](https://junglewise.ai/threats/technologies/benoitc-hackney). Vendors: [Benoitc](https://junglewise.ai/threats/vendors/benoitc).

## Quick answers

**Is CVE-2026-97200 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-97200 being exploited in the wild.

**How severe is CVE-2026-97200?** Informational severity, published 26 October 2026.

**Which products and versions are affected?** Benoitc Hackney 2.0.0-beta.1 before 4.9.0.

**Is there a fix for CVE-2026-97200?** Yes: fixed in hackney 4.9.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-97200 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-97200?** Check whether you run Benoitc Hackney at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in hackney 4.9.0

## Technical details

The vulnerability is an unbounded resource allocation in hackney's response body handling. The functions hackney_conn:read_full_body/2, and the HTTP/2 and HTTP/3 accumulators buffer all response chunks without enforcing size limits; when auto_decompress is enabled, zlib decompression further inflates data in memory in a single operation. An attacker operating an HTTP server can trigger this by sending an oversized or highly compressed response to any client that requests it.

## Affected products

- benoitc hackney 2.0.0-beta.1 before 4.9.0

## Timeline

- 2026-10-26: disclosed

## References

- [https://repo.hex.pm/](https://repo.hex.pm/)
- [https://github.com/](https://github.com/)

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