What’s Vulnerable › Vulnerabilities

CVE-2026-10099: XX-Net V5.16.6 WebSocket Frame Parsing Data Corruption via simple_http_server.py

• Severity: medium (CVSS 4.0 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-05-29 · updated 2026-10-06
• Weakness: CWE-1286

Description

XX-Net V5.16.6 contains a WebSocket frame parsing vulnerability in the WebSocket_receive_worker routine of simple_http_server.py that allows attackers to cause corrupted application data by sending unmasked WebSocket frames. The server unconditionally reads 4 bytes as a masking key regardless of whether the MASK bit is set in the frame header, causing the first 4 bytes of payload to be consumed as a mask key and the remaining payload to be incorrectly XOR-decoded, resulting in data corruption alongside missing RSV bit, opcode, and FIN fragmentation validations.

References

• https://github.com/XX-net/XX-Net/commit/a68b972a84ed6e52df9f30237cf47493b9231b53
• https://github.com/XX-net/XX-Net/issues/14169
• https://github.com/XX-net/XX-Net/pull/14170
• https://www.vulncheck.com/advisories/xx-net-websocket-frame-parsing-data-corruption-via-simple-http-server-py

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