Off-by-one error in the WebSocketHandshake::readServerHandshake function in websockets/WebSocketHandshake.cpp in WebCore in WebKit before r56380, as used in Qt and other products, allows remote websockets servers to cause a denial of service (memory corruption) or possibly have unspecified other impact via an upgrade header that is long and invalid.
Conclusion & alert: CVE-2010-1766 is rated Moderate Risk (59.2/100): CVSS High severity, with medium exploitation likelihood (EPSS 2.35%). Mandatory action: Review affected assets and schedule remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2025-07-13 | 2.58% | 2.35% | -0.23% |
| 2 | 2025-03-30 | 3.87% | 2.58% | -1.28% |
| 3 | 2025-03-29 | — | 3.87% | — |
Full EPSS history (8 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 7.5 | 2.0 | HIGH |
|
10.0 | 6.4 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
redhat
|
critical | — | https://access.redhat.com/security/cve/CVE-2010-1766 |
ubuntu
|
medium | CVE-2010-1766 medium priority: Ubuntu including 3 source packages (chromium-browser, qt4-x11, webkit), 27 status rows across 9 suites (dapper, hardy, jaunty, karmic, lucid, maverick, natty, oneiric, upstream): ignored 9, not-affected 9, DNE 5, needs-triage 3, released 1. | https://ubuntu.com/security/CVE-2010-1766 |