benoitc hackney up to 4.0.0 src/hackney_socks5.erl Timeout resource consumption

Summaryinfo

A vulnerability was found in benoitc hackney up to 4.0.0 and classified as problematic. This affects an unknown function of the file src/hackney_socks5.erl. Such manipulation of the argument Timeout leads to resource consumption. This vulnerability is documented as CVE-2026-47071. The attack can be executed remotely. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in benoitc hackney up to 4.0.0. It has been rated as problematic. Affected by this issue is an unknown code of the file src/hackney_socks5.erl. The manipulation of the argument Timeout with an unknown input leads to a resource consumption vulnerability. Using CWE to declare the problem leads to CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. Impacted is availability. CVE summarizes:

Uncontrolled Resource Consumption vulnerability in benoitc hackney allows Flooding. The SOCKS5 transport in src/hackney_socks5.erl correctly applies the caller-supplied timeout to the SOCKS5 negotiation phase, but then upgrades the connection to TLS using the two-argument form ssl:connect/2, which defaults to an infinite timeout. The Timeout value is in scope at the call site but is not forwarded. A hostile SOCKS5 proxy that completes the SOCKS5 handshake normally and then goes silent (or sends a partial TLS ServerHello and stalls) will cause the connecting process to block indefinitely, regardless of the connect_timeout or recv_timeout options supplied by the caller. This issue affects hackney: from 0.10.0 before 4.0.1.

The weakness was released by Peter Ullrich and Jonatan Männchen. The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-47071 since 05/18/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1499.

Upgrading to version 4.0.1 eliminates this vulnerability. Applying the patch 5ccdab725c561a6f03d05a51f2d0664f98236dae is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-31685). Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

• benoitc

Name

• hackney

Version

• 4.0

Website

• Product: https://github.com/benoitc/hackney/

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Once again VulDB remains the best source for vulnerability data.

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