CVE-2026-47074: ex-aws ex_aws_sns signature bypass in verify_message/1

CVE-2026-47074 · Severity: high · CVSS 8.7 · Published 2026-05-28

Hackney, a popular HTTP client library for Erlang, contains a vulnerability when using the HTTP/3 transport protocol. A malicious server can send data very slowly in a way that prevents the client's timeout from ever triggering, while simultaneously forcing the client to store an unlimited amount of data in memory. This can lead to a denial-of-service condition where the application crashes or the entire system runs out of memory.

Technologies: Benoit Chesneau Hackney. Vendors: Benoit Chesneau.

Quick answers

Is CVE-2026-47074 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-47074 being exploited in the wild.
How severe is CVE-2026-47074?
High severity, with a CVSS score of 8.7, published 28 May 2026.
Which products and versions are affected?
Benoit Chesneau Hackney >= 4.0.0, < 4.0.1; ExAws.SNS >= 2.0.1, < 2.3.5.
Is there a fix for CVE-2026-47074?
A patch was published on 2026-06-26: GitHub Advisory reviewed/updated date Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-47074 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-47074?
Check whether you run Benoit Chesneau Hackney or ExAws.SNS 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.

Technical details

The vulnerability exists in `hackney_h3:await_response_loop/6` within `src/hackney_h3.erl`. The loop accumulates HTTP/3 response body chunks in memory without a size limit (`max_body` check). Furthermore, the `after Timeout` clause acts as a per-message inactivity timer rather than a monotonic wall-clock deadline; receiving any `stream_data` chunk or housekeeping message resets the timer. An attacker-controlled HTTP/3 server can drip small chunks just before the timeout expires, causing linear memory growth until the BEAM process heap is exhausted (OOM). This only affects the HTTP/3 transport; the default TCP/TLS transports are not impacted. The issue is fixed in version 4.0.1.

Affected products

  • benoitc hackney >= 4.0.0, < 4.0.1

Identifiers

  • CVE-2026-47074
  • GHSA-jq4m-q6p2-8gwc

Timeline

  • 2026-05-25: disclosed
  • 2026-05-28: advisory: NVD publication date
  • 2026-06-26: patched: GitHub Advisory reviewed/updated date

References

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.