Client crash via unbounded WebSocket buffers
Published May 25, 2026 · Updated May 25, 2026
Uncontrolled resource consumption in hackney 2.0.0 through 4.0.0 allows remote attackers to crash clients through WebSocket responses. The read_handshake_response/3 buffer, frame parsers, and frag_buffer append attacker-controlled bytes without total size limits. Exploitation requires a client connection to an attacker-controlled WebSocket server and exhausts process or node memory without affecting data integrity.
Summary
What happened
Uncontrolled resource consumption in hackney 2.0.0 through 4.0.0 allows remote attackers to crash clients through WebSocket responses. The read_handshake_response/3 buffer, frame parsers, and frag_buffer append attacker-controlled bytes without total size limits. Exploitation requires a client connection to an attacker-controlled WebSocket server and exhausts process or node memory without affecting data integrity.
The record
- CVE
- CVE-2026-47073
- 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
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=2.0.0 <4.0.1
- Affected versionversion=690cecaf236fba49526da404a5bc889a24367a3e <ce0109e2970ace6e20ff29bae9d05c3ac22ec6dc
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
- Upstream WebSocket buffer-exhaustion proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo