Application-data corruption via unmasked WebSocket frames
Published May 29, 2026 · Updated May 29, 2026
Improper WebSocket frame validation in XX-Net 5.16.6 allows local users to corrupt application data via unmasked frames. WebSocket_receive_worker reads four payload bytes as a masking key when the MASK bit is clear, then consumes those bytes and XOR-decodes the remaining payload with the false key. The listener binds to 127.0.0.1 by default, while Allow Remote exposes it on 0.0.0.0; the demonstrated consequence is limited to message corruption.
Summary
What happened
Improper WebSocket frame validation in XX-Net 5.16.6 allows local users to corrupt application data via unmasked frames. WebSocket_receive_worker reads four payload bytes as a masking key when the MASK bit is clear, then consumes those bytes and XOR-decodes the remaining payload with the false key. The listener binds to 127.0.0.1 by default, while Allow Remote exposes it on 0.0.0.0; the demonstrated consequence is limited to message corruption.
The record
- CVE
- CVE-2026-10099
- Published
- May 29, 2026
- Updated
- May 29, 2026
- Vendor
- XX-Net
- Product
- XX-Net
- Classifications
- CWE-1286
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 29, 2026CVE publishedPublication date reported by the CVE source.
- May 29, 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?
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- Affected versionversion=0 <=43aec6f
- Affected versionversion=0 <=5.16.6
What conditions does exploitation require?
What is affected?
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
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Technologies
Your stack
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Your stack
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