CVE-2026-47071
Fix: benoitc/hackney@5ccdab7CVE-2026-47071 is a Uncontrolled Resource Consumption vulnerability in hackney. O3 Security confirms whether CVE-2026-47071 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
SOCKS5 TLS upgrade ignores caller timeout in hackney
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-47071.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
hackneyReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Hex packages — download data is not available via public APIs for these ecosystems.
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💧Hex | hackney | ≥ 0.10.0&&< 4.0.1 | 4.0.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for hackney. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update hackney to 4.0.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-47071 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-47071 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-47071. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-47071 in your dependencies?
O3 detects CVE-2026-47071 across Hex dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.