Vulnerability in Xx-Net
CVE-2026-10099
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.0 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.
EPSS exploit prediction
EPSS: 0.001 (1.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 2nd percentile — 1.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: 0.000
Affected products
- Xx-Net — versions 0
Weakness classification (CWE)
References
- github.com/XX-net/XX-Net/commit/a68b972a84ed6e52df9f30237cf47493b9231b53 (patch)
- github.com/XX-net/XX-Net/issues/14169 (issue-tracking)
- github.com/XX-net/XX-Net/pull/14170 (issue-tracking, technical-description)
- www.vulncheck.com/advisories/xx-net-websocket-frame-parsing-data-corruption-via… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-10099?
- CVE-2026-10099 is a medium-severity vulnerability in Xx-Net, classified under CWE-1286. CVSS score: 4.0/10. Published 2026-05-29.
- How severe is CVE-2026-10099?
- Medium severity. CVSS v3 base score is 4.0 out of 10.