CVE-2026-47071CWE-400

SOCKS5 TLS upgrade ignores caller timeout in hackney

High · published May 25, 2026

CVSS v4.0
8.2
EPSS
1%
Percentile
52.6
In the wild
Unconfirmed
What it is

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 record
Technical detail
CVSS v4.0
8.2 · HIGH
Vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
EPSS
0.00700 · 52.6th percentile
Weakness
CWE-400 · Uncontrolled Resource Consumption
Published
2026-05-25T14:00Z
EPSS history
Timeline
  • 25 MAY 14:00Z
    SOCKS5 TLS upgrade ignores caller timeout in hackney
    cvelistv5