Is CVE-2026-47071 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-47071 being exploited in the wild.

How severe is CVE-2026-47071?

High severity, with a CVSS score of 8.2, published 25 May 2026.

Which products and versions are affected?

benoitc hackney >= 0.10.0, < 4.0.1.

Is there a fix for CVE-2026-47071?

A patch was published on 2026-06-26. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-47071 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-47071?

Check whether anything you run is named in the advisory. 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.

CVE-2026-47071: benoitc hackney uncontrolled resource consumption in SOCKS5 TLS upgrade

Q: Is there a fix for CVE-2026-47071?

A patch was published on 2026-06-26. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2026-47071 attacked?

It is attacked over the network, in a software library.

Q: Am I affected by CVE-2026-47071?

Check whether anything you run is named in the advisory. 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.

CVE-2026-47071 · Severity: high · CVSS 8.2 · Published 2026-05-25

Hackney, a popular HTTP client library for the Erlang ecosystem, contains a flaw when routing traffic through SOCKS5 proxies. An attacker-controlled or compromised proxy can stall the connection process indefinitely during the secure connection (TLS) setup phase. This can lead to a denial-of-service condition by exhausting system resources, such as memory and available network connections, as the application waits forever for a response that never arrives.

Quick answers

Is CVE-2026-47071 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-47071 being exploited in the wild.
How severe is CVE-2026-47071?: High severity, with a CVSS score of 8.2, published 25 May 2026.
Which products and versions are affected?: benoitc hackney >= 0.10.0, < 4.0.1.
Is there a fix for CVE-2026-47071?: A patch was published on 2026-06-26. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-47071 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-47071?: Check whether anything you run is named in the advisory. 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 `src/hackney_socks5.erl` where the code performs a post-handshake TLS upgrade. While the SOCKS5 negotiation correctly honors user-supplied timeouts, the subsequent call to `ssl:connect/2` uses the two-argument form which defaults to an infinite timeout. An attacker-controlled SOCKS5 proxy can complete the initial handshake and then stall the TLS exchange (e.g., by not sending a ServerHello). This causes the calling Erlang process to block indefinitely, bypassing `connect_timeout` and `recv_timeout` settings. The issue is fixed in version 4.0.1 by ensuring the timeout value is correctly passed to the SSL connection call.

Affected products

benoitc hackney >= 0.10.0, < 4.0.1

Identifiers

CVE-2026-47071
GHSA-gp9c-pm5m-5cxr

Timeline

2026-05-25: disclosed
2026-06-26: advisory
2026-06-26: patched

References

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