High severity · published May 25, 2026
CVE-2026-47071
SOCKS5 TLS upgrade ignores caller timeout in hackney
7.5
CVSS
0.8%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.8% · higher than 55% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
HA
hackney · benoitc
0.10.0 before 4.0.1; 34cdbd1d20a282aacc286a89327465a3925b4c5d before 5ccdab725c561a6f03d05a51f2d0664f98236dae · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-47071
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-47071
Patch
https://cna.erlef.org/cves/CVE-2026-47071.html
Patch
https://github.com/benoitc/hackney/commit/5ccdab725c561a6f03d05a51f2d0664f98236dae
Exploit
https://github.com/benoitc/hackney/security/advisories/GHSA-gp9c-pm5m-5cxr
Patch
https://osv.dev/vulnerability/EEF-CVE-2026-47071
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