GHSA-4mp9-239f-g9hg: Netty: WebSockets V07/V08 handshaker missing Connection/Upgrade validation
Summary
An attacker can force WebSocket upgrade via the lax V07 (or V08) handshaker by sending Sec-WebSocket-Version: 7 and omitting Connection: Upgrade / Upgrade: websocket headers, completing a protocol switch that a proxy would not recognize as an Upgrade request and enabling HTTP request smuggling / protocol-confusion attacks.
Details
Original advisory: https://github.com/advisories/GHSA-4mp9-239f-g9hg
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Low exploitation riskCVE-2026-598980.27% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 18% of all scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-59898 | coverage & exploitation status | NVD · CVE.org |
Same CVEs, other sources
How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.
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