TI-2026-34673 Aliases CVE-2026-47071 GHSA-gp9c-pm5m-5cxr

SOCKS5 TLS upgrade ignores caller timeout in hackney

HIGH 75CWE-400Published 2026-05-25 · Updated 2026-05-27

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Attack requirements: Present
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-400.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00753 55th percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by NVD

Fix Fixed hackney (benoitc): 4.0.1hackney (Hex): 4.0.1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: Yes
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
benoitc	hackney	0.10.0 to before 4.0.1	4.0.1	Patch available	CNA
—	hackney (Hex)	0.10.0 to before 4.0.1	4.0.1	Patch available	GHSA-gp9c-pm5m-5cxr

hackney Vendorbenoitc Affected 0.10.0 to before 4.0.1 Fixed in 4.0.1 Patch available CNA
hackney (Hex) Vendor— Affected 0.10.0 to before 4.0.1 Fixed in 4.0.1 Patch available GHSA-gp9c-pm5m-5cxr

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:benoitc:hackney::::::::	0.10.0 to before 4.0.1	Vulnerable	benoitc

cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:* Versions 0.10.0 to before 4.0.1 Vulnerable ·benoitc

Remediation

Fix · CNA hackney (benoitc) Fixed in 4.0.1
Fix · GHSA-gp9c-pm5m-5cxr hackney (Hex) Fixed in 4.0.1 Advisory →

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

Release · 2026-05-25
benoitc hackney 4.0.1
10 records Highest priority Priority HIGH 6 HIGH, 4 MEDIUM
Other records, highest priority first
- TI-2026-34675 Unbounded memory consumption in WebSocket client in hackneyPriority HIGH 77
- TI-2026-34669 Atom table exhaustion via unrecognized URL schemes in hackneyPriority HIGH 77
- TI-2026-34668 Infinite loop in Alt-Svc header parser in hackneyPriority HIGH 77
Show all 10 records →

Timeline

2026-10-02 Threatist record created from CVE-2026-47071
2026-10-03 Alias added: GHSA-gp9c-pm5m-5cxr

References

Exploit 1

https://github.com/benoitc/hackney/security/advisories/GHSA-gp9c-pm5m-5cxr

Patch 3

Advisory 1

https://nvd.nist.gov/vuln/detail/CVE-2026-47071

Other 1

https://github.com/benoitc/hackney

TI-2026-34675 Unbounded memory consumption in WebSocket client in hackney CVSS 4.0HIGH 8.7
TI-2026-34669 Atom table exhaustion via unrecognized URL schemes in hackney CVSS 4.0HIGH 8.7
TI-2026-34668 Infinite loop in Alt-Svc header parser in hackney CVSS 4.0HIGH 8.7
TI-2026-34679 Unbounded body accumulation in HTTP/3 response loop in hackney CVSS 4.0HIGH 8.2
TI-2026-34674 CRLF injection in WebSocket upgrade request in hackney CVSS 4.0MEDIUM 6.9
TI-2026-34678 SSRF allowlist bypass via percent-encoded host in hackney CVSS 4.0MEDIUM 6.9

See all 9 →

Sources

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