Connection exhaustion via unbounded proxy TLS handshake
Published May 25, 2026 · Updated May 25, 2026
Resource exhaustion in Benoit Chesneau hackney 0.10.0 through 4.0.0 allows remote attackers to hang proxied HTTPS connections. The SOCKS5 proxy TLS-upgrade path calls ssl:connect/2 without forwarding the caller-supplied timeout, leaving each handshake unbounded. Control of, or a man-in-the-middle position on, the configured proxy is required; a stalled handshake pins one Erlang process and socket per request indefinitely.
Summary
What happened
Resource exhaustion in Benoit Chesneau hackney 0.10.0 through 4.0.0 allows remote attackers to hang proxied HTTPS connections. The SOCKS5 proxy TLS-upgrade path calls ssl:connect/2 without forwarding the caller-supplied timeout, leaving each handshake unbounded. Control of, or a man-in-the-middle position on, the configured proxy is required; a stalled handshake pins one Erlang process and socket per request indefinitely.
The record
- CVE
- CVE-2026-47071
- Published
- May 25, 2026
- Updated
- May 25, 2026
- Vendor
- Benoit Chesneau
- Product
- Hackney
- Classifications
- CWE-400, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 25, 2026CVE publishedPublication date reported by the CVE source.
- May 25, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0.10.0 <4.0.1
- Affected versionversion=34cdbd1d20a282aacc286a89327465a3925b4c5d <5ccdab725c561a6f03d05a51f2d0664f98236dae
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Hostile SOCKS5 proxy stalled-handshake proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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